Page 1
Pinnacle Chemistry
Chemistry
Structure of Atom
Q.1. Identify whether the given
statements about ionisation energy are
correct or incorrect.
Statement A:
The ionisation energy of an atom is the
amount of energy that is required to
remove an electron from a mole of
atoms in the gas phase.
Statement B:
The ionisation energy increases from top
to bottom in groups and decreases from
left to right across a period.
SSC CPO 04/10/2023 (Afternoon)
(a) Only Statement B is correct
(b) Only Statement A is correct
(c) Both Statements A and B are correct
(d) Both Statements A and B are
incorrect
Sol.1.(b) Only Statement A is correct.
The ionization energy decreases from
top to bottom in groups, and increases
from left to right across a period. Thus,
helium has the largest ionization energy,
while Caesium has the lowest.
Q.2. In which year did Carl Anderson
discover a positively charged particle
called "positron' whose mass appears to
be equal to the mass of an electron?
SSC CHSL 07/08/2023 (3rd shift)
(a) 1912 (b) 1932 (c) 1922 (d) 1942
Sol.2.(b) 1932. Electron - J.J. Thomson
(1897). Proton - E. Rutherford. Neutron -
James Chadwick (1932).
Q.3. In which year did Niels Bohr propose
a theory for the hydrogen atom based on
the quantum theory that some physical
quantities take only discrete values?
SSC CHSL 09/08/2023 (1st shift)
(a) 1919 (b) 1921 (c) 1909 (d) 1913
Sol.3.(d) 1913. Niels Bohr received the
Nobel Prize in 1922 "for his services in
the investigation of the structure of
atoms and of the radiation emanating
from them" .
Q.4. Which are the four quantum
numbers for an electron present in 4f
orbital?
SSC CHSL 03/08/2023 (1st shift)
(a) n = 4, = 3, m = +1, s = + ??
1
2
(b) n = 3, = 2, m = - 2, s = + ??
1
2
(c) n = 4, = 4, m = - 4, s = - ??
1
2
(d) n = 4, = 3, m = +4, s = + ??
1
2
Sol.4.(a) n = 4, l = 3, m = + 1, s = + .
1
2
There are four quantum numbers:
Principal (n) - It refers to the electron
shell with the most electrons, giving the
electron's likely distance from the
nucleus. Azimuthal (l) - It is de?ned as
the determination of the shape of an
orbital. Magnetic (m) - The subshell's
overall number of orbitals and their
orientation. Spin (s) - The values of n, l,
and m
l
have no bearing on the electron.
The 4s subshell contains 1 orbital and
can hold up to 2 electrons. The 4p
subshell contains 3 orbitals and can hold
up to 6 electrons. The 4d subshell
contains 5 orbitals and can hold up to 10
electrons.The 4f subshell has 7 orbitals
and can hold up to 14 electrons.
Q.5. The correct electronic con?guration
of Cu is :
SSC CHSL 07/08/2023 (1st shift)
(a) [Ar]3d
9
4s
2
(b) [Kr]3d
9
4s
2
(c) [Kr]3d
10
4s
1
(d) [Ar]3d
10
4s
1
Sol.5.(d) [Ar]3d
10
4s
1
. Copper (Cu) -
Atomic number (29), Electronic
con?guration - 1s² 2s² 2p6 3s² 3p6 4s¹
3d
10
or [Ar]3d
10
4s
1
.
Q.6. What does it mean when an object
has a positive charge ?
SSC MTS 19/05/2023 (Morning)
(a) It has more electrons than protons
(b) It has more protons than electrons
(c) It has more neutrons than electrons
(d) It has more neutrons than protons
Sol.6.(b) An electron is negatively
charged particle and protons are
positively charged particles.
Q.7. What is the relative charge of a
proton and neutron?
SSC MTS 15/06/2023 (Afternoon)
(a) -1 and +1 respectively
(b) +1 and -1 respectively
(c) +1 and 0 respectively
(d) -1 and 0 respectively
Sol.7.(c) +1 and 0 respectively.
Q.8. Which of the following pairs of
'number - composition' is correct?
I. Atomic number - number of protons
II. Mass number - Sum of number of
neutrons and protons
SSC CHSL 09/03/2023 (4th Shift)
(a) Only I (b) Neither I nor II
(c) Both I and II (d) Only II
Sol.8.(c) Both I and II. As atomic number
increases, subsequently mass number
also increases.
Q.9. What is the atomic mass of sodium?
SSC CHSL 13/03/2023 (1st Shift)
(a) 32 (b) 40 (c) 23 (d) 12
Sol.9.(c) 23. Sodium (Na) is an alkali
metal. Atomic number - 11, Group - 1 and
Period - 3, Sodium is a solid at room
temperature. Uses - Soaps, the puri?cation
of molten metals and sodium vapour
lamps.
Q.10. Which of the following is the
correct representation of number of
atoms?
SSC CHSL 14/03/2023 (4th Shift)
(a) ( ) ×
?????????? ????????
?????????? ????????
???????????????? ????????????
(b) ( ) ×
???????????????? ????????????
?????????? ????????
?????????? ????????
(c) ( ) ×
?????????? ????????
?????????? ????????
???????????????? ????????????
(d) ( ) ×
?????????? ????????
???????????????? ????????????
?????????? ????????
Sol.10.(a) ( ) × Avogadro
?????????? ????????
?????????? ????????
number . Avogadro number: 6.022 × 10²³.
Molar mass of a substance is the mass
(in grams) of one mole of the compound.
Q.11. What is the maximum number of
electrons that the third orbit or M-shell
can have?
SSC CHSL 21/03/2023 (2nd Shift)
(a) 32 (b) 8 (c) 18 (d) 2
Sol.11.(c) 18 . The maximum number of
electrons accommodated in a shell
based on principal quantum number (n).
It is represented by the formula 2n
2
.
K shell, n = 1, Max Electron = 2 × 1
2
= 2.
L shell, n = 2, Max Electron = 2 × 2
2
= 8.
M shell, n = 3, Max Electron = 2 × 3
2
= 18.
N shell, n = 4, Max Electron = 2 × 4
2
= 32.
Q.12. Which of the following statements
is NOT correct regarding Rutherford's
nuclear model of an atom?
SSC CHSL 21/03/2023 (2nd Shift)
(a) The size of the nucleus is very large
as compared to the size of the atom.
(b) The electrons revolve around the
nucleus in circular paths.
(c) There is a positively charged centre in
an atom called the nucleus.
(d) Nearly all the mass of an atom
resides in the nucleus.
Sol.12.(a) According to Rutherford’s
nuclear model of an atom, nucleus is
very small in size as compared to the
size of the atom. Rutherford explained
the revolving of electrons around the
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Page 2
Pinnacle Chemistry
Chemistry
Structure of Atom
Q.1. Identify whether the given
statements about ionisation energy are
correct or incorrect.
Statement A:
The ionisation energy of an atom is the
amount of energy that is required to
remove an electron from a mole of
atoms in the gas phase.
Statement B:
The ionisation energy increases from top
to bottom in groups and decreases from
left to right across a period.
SSC CPO 04/10/2023 (Afternoon)
(a) Only Statement B is correct
(b) Only Statement A is correct
(c) Both Statements A and B are correct
(d) Both Statements A and B are
incorrect
Sol.1.(b) Only Statement A is correct.
The ionization energy decreases from
top to bottom in groups, and increases
from left to right across a period. Thus,
helium has the largest ionization energy,
while Caesium has the lowest.
Q.2. In which year did Carl Anderson
discover a positively charged particle
called "positron' whose mass appears to
be equal to the mass of an electron?
SSC CHSL 07/08/2023 (3rd shift)
(a) 1912 (b) 1932 (c) 1922 (d) 1942
Sol.2.(b) 1932. Electron - J.J. Thomson
(1897). Proton - E. Rutherford. Neutron -
James Chadwick (1932).
Q.3. In which year did Niels Bohr propose
a theory for the hydrogen atom based on
the quantum theory that some physical
quantities take only discrete values?
SSC CHSL 09/08/2023 (1st shift)
(a) 1919 (b) 1921 (c) 1909 (d) 1913
Sol.3.(d) 1913. Niels Bohr received the
Nobel Prize in 1922 "for his services in
the investigation of the structure of
atoms and of the radiation emanating
from them" .
Q.4. Which are the four quantum
numbers for an electron present in 4f
orbital?
SSC CHSL 03/08/2023 (1st shift)
(a) n = 4, = 3, m = +1, s = + ??
1
2
(b) n = 3, = 2, m = - 2, s = + ??
1
2
(c) n = 4, = 4, m = - 4, s = - ??
1
2
(d) n = 4, = 3, m = +4, s = + ??
1
2
Sol.4.(a) n = 4, l = 3, m = + 1, s = + .
1
2
There are four quantum numbers:
Principal (n) - It refers to the electron
shell with the most electrons, giving the
electron's likely distance from the
nucleus. Azimuthal (l) - It is de?ned as
the determination of the shape of an
orbital. Magnetic (m) - The subshell's
overall number of orbitals and their
orientation. Spin (s) - The values of n, l,
and m
l
have no bearing on the electron.
The 4s subshell contains 1 orbital and
can hold up to 2 electrons. The 4p
subshell contains 3 orbitals and can hold
up to 6 electrons. The 4d subshell
contains 5 orbitals and can hold up to 10
electrons.The 4f subshell has 7 orbitals
and can hold up to 14 electrons.
Q.5. The correct electronic con?guration
of Cu is :
SSC CHSL 07/08/2023 (1st shift)
(a) [Ar]3d
9
4s
2
(b) [Kr]3d
9
4s
2
(c) [Kr]3d
10
4s
1
(d) [Ar]3d
10
4s
1
Sol.5.(d) [Ar]3d
10
4s
1
. Copper (Cu) -
Atomic number (29), Electronic
con?guration - 1s² 2s² 2p6 3s² 3p6 4s¹
3d
10
or [Ar]3d
10
4s
1
.
Q.6. What does it mean when an object
has a positive charge ?
SSC MTS 19/05/2023 (Morning)
(a) It has more electrons than protons
(b) It has more protons than electrons
(c) It has more neutrons than electrons
(d) It has more neutrons than protons
Sol.6.(b) An electron is negatively
charged particle and protons are
positively charged particles.
Q.7. What is the relative charge of a
proton and neutron?
SSC MTS 15/06/2023 (Afternoon)
(a) -1 and +1 respectively
(b) +1 and -1 respectively
(c) +1 and 0 respectively
(d) -1 and 0 respectively
Sol.7.(c) +1 and 0 respectively.
Q.8. Which of the following pairs of
'number - composition' is correct?
I. Atomic number - number of protons
II. Mass number - Sum of number of
neutrons and protons
SSC CHSL 09/03/2023 (4th Shift)
(a) Only I (b) Neither I nor II
(c) Both I and II (d) Only II
Sol.8.(c) Both I and II. As atomic number
increases, subsequently mass number
also increases.
Q.9. What is the atomic mass of sodium?
SSC CHSL 13/03/2023 (1st Shift)
(a) 32 (b) 40 (c) 23 (d) 12
Sol.9.(c) 23. Sodium (Na) is an alkali
metal. Atomic number - 11, Group - 1 and
Period - 3, Sodium is a solid at room
temperature. Uses - Soaps, the puri?cation
of molten metals and sodium vapour
lamps.
Q.10. Which of the following is the
correct representation of number of
atoms?
SSC CHSL 14/03/2023 (4th Shift)
(a) ( ) ×
?????????? ????????
?????????? ????????
???????????????? ????????????
(b) ( ) ×
???????????????? ????????????
?????????? ????????
?????????? ????????
(c) ( ) ×
?????????? ????????
?????????? ????????
???????????????? ????????????
(d) ( ) ×
?????????? ????????
???????????????? ????????????
?????????? ????????
Sol.10.(a) ( ) × Avogadro
?????????? ????????
?????????? ????????
number . Avogadro number: 6.022 × 10²³.
Molar mass of a substance is the mass
(in grams) of one mole of the compound.
Q.11. What is the maximum number of
electrons that the third orbit or M-shell
can have?
SSC CHSL 21/03/2023 (2nd Shift)
(a) 32 (b) 8 (c) 18 (d) 2
Sol.11.(c) 18 . The maximum number of
electrons accommodated in a shell
based on principal quantum number (n).
It is represented by the formula 2n
2
.
K shell, n = 1, Max Electron = 2 × 1
2
= 2.
L shell, n = 2, Max Electron = 2 × 2
2
= 8.
M shell, n = 3, Max Electron = 2 × 3
2
= 18.
N shell, n = 4, Max Electron = 2 × 4
2
= 32.
Q.12. Which of the following statements
is NOT correct regarding Rutherford's
nuclear model of an atom?
SSC CHSL 21/03/2023 (2nd Shift)
(a) The size of the nucleus is very large
as compared to the size of the atom.
(b) The electrons revolve around the
nucleus in circular paths.
(c) There is a positively charged centre in
an atom called the nucleus.
(d) Nearly all the mass of an atom
resides in the nucleus.
Sol.12.(a) According to Rutherford’s
nuclear model of an atom, nucleus is
very small in size as compared to the
size of the atom. Rutherford explained
the revolving of electrons around the
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Pinnacle Chemistry
nucleus, however, he did not mention
how the electrons were placed inside,
which ended up making Rutherford’s
model an incomplete model of the atom.
Q.13. Which of the following pairs of
'elements - valency' is correct?
I. Boron - 2
II. Fluorine - 3
SSC CHSL 21/03/2023 (4th Shift)
(a) Neither I nor II (b) Both I and II
(c) Only II (d) Only I
Sol.13.(a) Neither I nor II. Valency -
Combining power of an element. Valency
of some elements : Aluminium (+3), Boron
(+3), ?uorine (-1).
Q.14. Which theory discusses the
relationship between ligand bonding and
degradation of d orbitals in metal
complexes and the geometry of metal
complexes and the splitting of d orbitals?
SSC CGL 05/12/2022 (4th Shift)
(a) Crystal ?eld theory (CFT)
(b) Ligand ?eld theory (LFT)
(c) Valence bond theory (VBT)
(d) Molecular orbital theory (MOT)
Sol.14.(a) Crystal ?eld theory: (1929,
developed by physicist Hans Bethe)
describes the breaking of orbital
degeneracy in transition metal
complexes due to the presence of
ligands.
Q.15. What kind of forces arise from
transient dipoles in atoms that induce
transient dipoles in nearby atoms,
produce an attractive force and are
signi?cant only over short distances
(~500 pm) ?
SSC CGL 02/12/2022 (1st Shift)
(a) Dipole-dipole forces
(b) London dispersion forces
(c) Dipole-induced dipole forces
(d) Hydrogen bond
Sol.15.(b) London Dispersion forces.
Dipole – Dipole Force is a form of
intermolecular force that occurs when a
polar molecule interacts with a non-polar
molecule . Dipole-induced dipole force is
a type of attractive force that operates
between the polar molecules having
permanent dipole and the molecules
lacking permanent dipole.
Q.16. In 1898, whose theory propounded
that the ions/groups bonded to the metal
by secondary bonding have spatial
arrangements corresponding to different
characteristics coordination number?
SSC CPO 09/11/2022 (Afternoon)
(a) Henry Taube (b) Alfred Werner
(c) Erich Huckel (d) Emil Fischer
Sol.16.(b) Alfred Werner. Nobel Prize for
Chemistry (1913). Henry Taube - Nobel
Prize in Chemistry (1983 - “for his studies
of the mechanisms of electron transfer in
metal complexes”).
Q.17. What is the atomicity of
Phosphorus?
SSC CPO 10/11/2022 (Evening)
(a) Poly-atomic (b) Monoatomic
(c) Diatomic (d) Tetra-atomic
Sol.17.(d) Tetra-atomic. Atomicity is the
total number of atoms present in a
molecule. Polyatomic (composed of
three or more atoms). Phosphorus was
?rst made by Hennig Brandt in 1669.
Q.18. Which formula is used to represent
the three-dimensional structures of
molecules using a two-dimensional
surface like a sheet of paper or a
computer screen?
SSC CPO 11/11/2022 (Evening)
(a) Bond-line formula
(b) Lewis structure formula
(c) Dash-wedge formula
(d) Condensed structural formula
Sol.18.(c) Dash-wedge formula. Bond -
line formula is used for every bond
represented as a line in a zigzag manner.
Q.19. In the electronic con?guration of
an atom, What does ‘n’ signify in the
formula 2n
2
?
SSC CHSL 27/05/2022 (Afternoon)
(a) The number of electrons
(b) The number of protons
(c) The number of the given shell from
the nucleus
(d) The number of valence electrons
present
Sol.19.(c) The electronic con?guration of
an element describes how electrons are
distributed in its atomic orbitals. The
maximum number of electrons that can
be accommodated in a shell is based on
the principal quantum number (n) and is
represented by the formula 2n
2
, where 'n'
is the shell number.
Q.20. According to Dalton’s atomic
theory, atoms combine in the ratio of
small whole numbers to form ______.
SSC MTS 2/11/2021 (Morning)
(a) neutrons (b) molecules
(c) protons (d) compounds
Sol.20.(d) Compounds . John Dalton is
considered the ‘Father of Modern Atomic
Theory’. Dalton's atomic theory (1808)
was the ?rst complete attempt to
describe all matter in terms of atoms and
their properties.
Q.21. If the size of the nucleus of an
atom is compared with a cricket ball,
then the radius of the atom is
approximately equal to how many
kilometers?
SSC CPO 23/11/2020 (Morning)
(a) 5 (b) 0.5 (c) 0.05 (d) 0.005
Sol.21.(a) 5 km. The radius of the atom
is 10
-10
m, and the radius of nucleus is
10
-15
m.
Q.22. The ?rst electron shell which is the
nearest to the nucleus never holds more
than 'n' electrons, where 'n' is equal to:
SSC CGL 6/03/2020 (Afternoon)
(a) 2 (b) 8 (c) 4 (d) 6
Sol.22.(a) 2. The maximum number of
electrons accommodated in a shell
based on principal quantum number (n).
It is represented by the formula 2n
2
.
K shell, n = 1, Max Electron = 2 × 1
2
= 2.
L shell, n = 2, Max Electron = 2 × 2
2
= 8.
M shell, n = 3, Max Electron = 2 × 3
2
= 18.
N shell, n = 4, Max Electron = 2 × 4
2
= 32.
Metals, Non-metals and Alloys
Q.23. Which of the following is NOT an
alkaline earth metal?
SSC Stenographer 12/10/2023 (Morning)
(a) Na (b) Mg (c) Ca (d) Be
Sol.23.(a) Na (Sodium) - It is an Alkali
metal. Alkaline earth metals: Beryllium
(Be, 4), Magnesium (Mg, 12), Calcium
(Ca, 20), Strontium (Sr, 38), Barium (Ba,
56), Radium (Ra, 88). They have two
electrons in their outermost shells. Alkali
metals: Lithium (Li, 3), Sodium (Na, 11),
Potassium (K, 19), Rubidium (Rb, 37),
Caesium (Cs, 55), Francium (Fr, 87).
Q.24. What is the name of the seventh
most abundant metal in the earth's crust,
which is derived from the medieval Latin
word 'Kalium' ?
SSC MTS 01/09/2023 (1st Shift)
(a) Aluminium (b) Magnesium
(c) Calcium (d) Potassium
Sol.24.(d) Potassium. It makes up 2.4%
by mass of the Earth crust. Aluminium is
the most abundant metal and Oxygen is
the most abundant non-metal found in
the earth's crust. Eight most abundant
elements in the Earth's crust are Oxygen
(O), Silicon (Si), Aluminium (Al), Calcium
(Ca), Iron (Fe), Magnesium (Mg), Sodium
(Na), and Potassium (K).
Q.25. Which chemical element with
atomic number 35 has a dark
reddish-brown liquid with a burning
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Page 3
Pinnacle Chemistry
Chemistry
Structure of Atom
Q.1. Identify whether the given
statements about ionisation energy are
correct or incorrect.
Statement A:
The ionisation energy of an atom is the
amount of energy that is required to
remove an electron from a mole of
atoms in the gas phase.
Statement B:
The ionisation energy increases from top
to bottom in groups and decreases from
left to right across a period.
SSC CPO 04/10/2023 (Afternoon)
(a) Only Statement B is correct
(b) Only Statement A is correct
(c) Both Statements A and B are correct
(d) Both Statements A and B are
incorrect
Sol.1.(b) Only Statement A is correct.
The ionization energy decreases from
top to bottom in groups, and increases
from left to right across a period. Thus,
helium has the largest ionization energy,
while Caesium has the lowest.
Q.2. In which year did Carl Anderson
discover a positively charged particle
called "positron' whose mass appears to
be equal to the mass of an electron?
SSC CHSL 07/08/2023 (3rd shift)
(a) 1912 (b) 1932 (c) 1922 (d) 1942
Sol.2.(b) 1932. Electron - J.J. Thomson
(1897). Proton - E. Rutherford. Neutron -
James Chadwick (1932).
Q.3. In which year did Niels Bohr propose
a theory for the hydrogen atom based on
the quantum theory that some physical
quantities take only discrete values?
SSC CHSL 09/08/2023 (1st shift)
(a) 1919 (b) 1921 (c) 1909 (d) 1913
Sol.3.(d) 1913. Niels Bohr received the
Nobel Prize in 1922 "for his services in
the investigation of the structure of
atoms and of the radiation emanating
from them" .
Q.4. Which are the four quantum
numbers for an electron present in 4f
orbital?
SSC CHSL 03/08/2023 (1st shift)
(a) n = 4, = 3, m = +1, s = + ??
1
2
(b) n = 3, = 2, m = - 2, s = + ??
1
2
(c) n = 4, = 4, m = - 4, s = - ??
1
2
(d) n = 4, = 3, m = +4, s = + ??
1
2
Sol.4.(a) n = 4, l = 3, m = + 1, s = + .
1
2
There are four quantum numbers:
Principal (n) - It refers to the electron
shell with the most electrons, giving the
electron's likely distance from the
nucleus. Azimuthal (l) - It is de?ned as
the determination of the shape of an
orbital. Magnetic (m) - The subshell's
overall number of orbitals and their
orientation. Spin (s) - The values of n, l,
and m
l
have no bearing on the electron.
The 4s subshell contains 1 orbital and
can hold up to 2 electrons. The 4p
subshell contains 3 orbitals and can hold
up to 6 electrons. The 4d subshell
contains 5 orbitals and can hold up to 10
electrons.The 4f subshell has 7 orbitals
and can hold up to 14 electrons.
Q.5. The correct electronic con?guration
of Cu is :
SSC CHSL 07/08/2023 (1st shift)
(a) [Ar]3d
9
4s
2
(b) [Kr]3d
9
4s
2
(c) [Kr]3d
10
4s
1
(d) [Ar]3d
10
4s
1
Sol.5.(d) [Ar]3d
10
4s
1
. Copper (Cu) -
Atomic number (29), Electronic
con?guration - 1s² 2s² 2p6 3s² 3p6 4s¹
3d
10
or [Ar]3d
10
4s
1
.
Q.6. What does it mean when an object
has a positive charge ?
SSC MTS 19/05/2023 (Morning)
(a) It has more electrons than protons
(b) It has more protons than electrons
(c) It has more neutrons than electrons
(d) It has more neutrons than protons
Sol.6.(b) An electron is negatively
charged particle and protons are
positively charged particles.
Q.7. What is the relative charge of a
proton and neutron?
SSC MTS 15/06/2023 (Afternoon)
(a) -1 and +1 respectively
(b) +1 and -1 respectively
(c) +1 and 0 respectively
(d) -1 and 0 respectively
Sol.7.(c) +1 and 0 respectively.
Q.8. Which of the following pairs of
'number - composition' is correct?
I. Atomic number - number of protons
II. Mass number - Sum of number of
neutrons and protons
SSC CHSL 09/03/2023 (4th Shift)
(a) Only I (b) Neither I nor II
(c) Both I and II (d) Only II
Sol.8.(c) Both I and II. As atomic number
increases, subsequently mass number
also increases.
Q.9. What is the atomic mass of sodium?
SSC CHSL 13/03/2023 (1st Shift)
(a) 32 (b) 40 (c) 23 (d) 12
Sol.9.(c) 23. Sodium (Na) is an alkali
metal. Atomic number - 11, Group - 1 and
Period - 3, Sodium is a solid at room
temperature. Uses - Soaps, the puri?cation
of molten metals and sodium vapour
lamps.
Q.10. Which of the following is the
correct representation of number of
atoms?
SSC CHSL 14/03/2023 (4th Shift)
(a) ( ) ×
?????????? ????????
?????????? ????????
???????????????? ????????????
(b) ( ) ×
???????????????? ????????????
?????????? ????????
?????????? ????????
(c) ( ) ×
?????????? ????????
?????????? ????????
???????????????? ????????????
(d) ( ) ×
?????????? ????????
???????????????? ????????????
?????????? ????????
Sol.10.(a) ( ) × Avogadro
?????????? ????????
?????????? ????????
number . Avogadro number: 6.022 × 10²³.
Molar mass of a substance is the mass
(in grams) of one mole of the compound.
Q.11. What is the maximum number of
electrons that the third orbit or M-shell
can have?
SSC CHSL 21/03/2023 (2nd Shift)
(a) 32 (b) 8 (c) 18 (d) 2
Sol.11.(c) 18 . The maximum number of
electrons accommodated in a shell
based on principal quantum number (n).
It is represented by the formula 2n
2
.
K shell, n = 1, Max Electron = 2 × 1
2
= 2.
L shell, n = 2, Max Electron = 2 × 2
2
= 8.
M shell, n = 3, Max Electron = 2 × 3
2
= 18.
N shell, n = 4, Max Electron = 2 × 4
2
= 32.
Q.12. Which of the following statements
is NOT correct regarding Rutherford's
nuclear model of an atom?
SSC CHSL 21/03/2023 (2nd Shift)
(a) The size of the nucleus is very large
as compared to the size of the atom.
(b) The electrons revolve around the
nucleus in circular paths.
(c) There is a positively charged centre in
an atom called the nucleus.
(d) Nearly all the mass of an atom
resides in the nucleus.
Sol.12.(a) According to Rutherford’s
nuclear model of an atom, nucleus is
very small in size as compared to the
size of the atom. Rutherford explained
the revolving of electrons around the
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nucleus, however, he did not mention
how the electrons were placed inside,
which ended up making Rutherford’s
model an incomplete model of the atom.
Q.13. Which of the following pairs of
'elements - valency' is correct?
I. Boron - 2
II. Fluorine - 3
SSC CHSL 21/03/2023 (4th Shift)
(a) Neither I nor II (b) Both I and II
(c) Only II (d) Only I
Sol.13.(a) Neither I nor II. Valency -
Combining power of an element. Valency
of some elements : Aluminium (+3), Boron
(+3), ?uorine (-1).
Q.14. Which theory discusses the
relationship between ligand bonding and
degradation of d orbitals in metal
complexes and the geometry of metal
complexes and the splitting of d orbitals?
SSC CGL 05/12/2022 (4th Shift)
(a) Crystal ?eld theory (CFT)
(b) Ligand ?eld theory (LFT)
(c) Valence bond theory (VBT)
(d) Molecular orbital theory (MOT)
Sol.14.(a) Crystal ?eld theory: (1929,
developed by physicist Hans Bethe)
describes the breaking of orbital
degeneracy in transition metal
complexes due to the presence of
ligands.
Q.15. What kind of forces arise from
transient dipoles in atoms that induce
transient dipoles in nearby atoms,
produce an attractive force and are
signi?cant only over short distances
(~500 pm) ?
SSC CGL 02/12/2022 (1st Shift)
(a) Dipole-dipole forces
(b) London dispersion forces
(c) Dipole-induced dipole forces
(d) Hydrogen bond
Sol.15.(b) London Dispersion forces.
Dipole – Dipole Force is a form of
intermolecular force that occurs when a
polar molecule interacts with a non-polar
molecule . Dipole-induced dipole force is
a type of attractive force that operates
between the polar molecules having
permanent dipole and the molecules
lacking permanent dipole.
Q.16. In 1898, whose theory propounded
that the ions/groups bonded to the metal
by secondary bonding have spatial
arrangements corresponding to different
characteristics coordination number?
SSC CPO 09/11/2022 (Afternoon)
(a) Henry Taube (b) Alfred Werner
(c) Erich Huckel (d) Emil Fischer
Sol.16.(b) Alfred Werner. Nobel Prize for
Chemistry (1913). Henry Taube - Nobel
Prize in Chemistry (1983 - “for his studies
of the mechanisms of electron transfer in
metal complexes”).
Q.17. What is the atomicity of
Phosphorus?
SSC CPO 10/11/2022 (Evening)
(a) Poly-atomic (b) Monoatomic
(c) Diatomic (d) Tetra-atomic
Sol.17.(d) Tetra-atomic. Atomicity is the
total number of atoms present in a
molecule. Polyatomic (composed of
three or more atoms). Phosphorus was
?rst made by Hennig Brandt in 1669.
Q.18. Which formula is used to represent
the three-dimensional structures of
molecules using a two-dimensional
surface like a sheet of paper or a
computer screen?
SSC CPO 11/11/2022 (Evening)
(a) Bond-line formula
(b) Lewis structure formula
(c) Dash-wedge formula
(d) Condensed structural formula
Sol.18.(c) Dash-wedge formula. Bond -
line formula is used for every bond
represented as a line in a zigzag manner.
Q.19. In the electronic con?guration of
an atom, What does ‘n’ signify in the
formula 2n
2
?
SSC CHSL 27/05/2022 (Afternoon)
(a) The number of electrons
(b) The number of protons
(c) The number of the given shell from
the nucleus
(d) The number of valence electrons
present
Sol.19.(c) The electronic con?guration of
an element describes how electrons are
distributed in its atomic orbitals. The
maximum number of electrons that can
be accommodated in a shell is based on
the principal quantum number (n) and is
represented by the formula 2n
2
, where 'n'
is the shell number.
Q.20. According to Dalton’s atomic
theory, atoms combine in the ratio of
small whole numbers to form ______.
SSC MTS 2/11/2021 (Morning)
(a) neutrons (b) molecules
(c) protons (d) compounds
Sol.20.(d) Compounds . John Dalton is
considered the ‘Father of Modern Atomic
Theory’. Dalton's atomic theory (1808)
was the ?rst complete attempt to
describe all matter in terms of atoms and
their properties.
Q.21. If the size of the nucleus of an
atom is compared with a cricket ball,
then the radius of the atom is
approximately equal to how many
kilometers?
SSC CPO 23/11/2020 (Morning)
(a) 5 (b) 0.5 (c) 0.05 (d) 0.005
Sol.21.(a) 5 km. The radius of the atom
is 10
-10
m, and the radius of nucleus is
10
-15
m.
Q.22. The ?rst electron shell which is the
nearest to the nucleus never holds more
than 'n' electrons, where 'n' is equal to:
SSC CGL 6/03/2020 (Afternoon)
(a) 2 (b) 8 (c) 4 (d) 6
Sol.22.(a) 2. The maximum number of
electrons accommodated in a shell
based on principal quantum number (n).
It is represented by the formula 2n
2
.
K shell, n = 1, Max Electron = 2 × 1
2
= 2.
L shell, n = 2, Max Electron = 2 × 2
2
= 8.
M shell, n = 3, Max Electron = 2 × 3
2
= 18.
N shell, n = 4, Max Electron = 2 × 4
2
= 32.
Metals, Non-metals and Alloys
Q.23. Which of the following is NOT an
alkaline earth metal?
SSC Stenographer 12/10/2023 (Morning)
(a) Na (b) Mg (c) Ca (d) Be
Sol.23.(a) Na (Sodium) - It is an Alkali
metal. Alkaline earth metals: Beryllium
(Be, 4), Magnesium (Mg, 12), Calcium
(Ca, 20), Strontium (Sr, 38), Barium (Ba,
56), Radium (Ra, 88). They have two
electrons in their outermost shells. Alkali
metals: Lithium (Li, 3), Sodium (Na, 11),
Potassium (K, 19), Rubidium (Rb, 37),
Caesium (Cs, 55), Francium (Fr, 87).
Q.24. What is the name of the seventh
most abundant metal in the earth's crust,
which is derived from the medieval Latin
word 'Kalium' ?
SSC MTS 01/09/2023 (1st Shift)
(a) Aluminium (b) Magnesium
(c) Calcium (d) Potassium
Sol.24.(d) Potassium. It makes up 2.4%
by mass of the Earth crust. Aluminium is
the most abundant metal and Oxygen is
the most abundant non-metal found in
the earth's crust. Eight most abundant
elements in the Earth's crust are Oxygen
(O), Silicon (Si), Aluminium (Al), Calcium
(Ca), Iron (Fe), Magnesium (Mg), Sodium
(Na), and Potassium (K).
Q.25. Which chemical element with
atomic number 35 has a dark
reddish-brown liquid with a burning
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pungent odour ?
SSC MTS 06/09/2023 (1st Shift)
(a) Tennessine (b) Chlorine
(c) Astatine (d) Bromine
Sol.25.(d) Bromine (Br) is the third
halogen, a nonmetal in group 17 of the
periodic table. Products containing
bromine used in agriculture and
sanitation and as ?re retardants.
Q.26. An image of which of the following
elements is shown by the map of Cyprus
from which the element got its name ?
SSC MTS 13/09/2023 (2nd Shift)
(a) Silver (b) Cobalt
(c) Copper (d) Sulphur
Sol.26.(c) Copper (Cu, Atomic no 29). It
is a good conductor of heat and
electricity. It is in group 11, period 4 and
block ‘d’ of the periodic table. It was the
?rst metal used by man on earth.
Q.27. Which radioactive isotope has a
half-life of 5770 years, which is
commonly used to estimate the age of
organic materials such as paper and
parchment ?
SSC CHSL 08/08/2023 (1st shift)
(a)
9
C (b)
12
C (c)
14
C (d)
17
C
Sol.27.(c)
14
C - It is an unstable and
weakly radioactive isotope of carbon.
Three Natural isotopes of carbon :
12
C,
13
C and
14
C. Isotopes - Atoms of the
same element having the same atomic
number but different mass numbers. For
example, take the case of hydrogen
atom, it has three atomic species,
namely protium (
1
1
H), deuterium (
2
1
H or
D) and tritium (
3
1
H or T). The atomic
number of each one is 1, but the mass
number is 1, 2 and 3, respectively.
Q.28. Which metal ion released from the
tannery industry causes acute water
pollution?
SSC CHSL 09/08/2023 (1st shift)
(a) Mg (b) As (c) Cr (d) Zn
Sol.28.(c) Chromium (Cr). Tannery
Wastewaters: It contains Hairs, proteins,
acids, alkalis, chromium salts, sulphides,
chlorides, tannins, solvents, dyes.
Q.29. What is the most stable mineral
during the process of weathering?
SSC CHSL 10/08/2023 (1st shift)
(a) Quartz (b) Olivine
(c) Pyroxene (d) Amphibole
Sol.29.(a) Quartz (felsic mineral). Iron
oxides, Al-hydroxides, clay minerals and
quartz are the most stable weathered
products whereas highly soluble
minerals like halite are the least stable.
Silicates fall within the middle range.
Ma?c silicates like olivine, pyroxene or
amphibole breakdown relatively easily.
Weathering - The breaking down or
dissolving of rocks and minerals on
Earth's surface. Types of weathering:
Chemical, Physical and Biological
Weathering.
Q.30. From which Latin word is the s
block element calcium derived?
SSC CGL 14/07/2023 (3rd shift)
(a) Calx (b) Calum (c) Coleus (d) Calcio
Sol.30.(a) Calx (calcium hydroxide) .
Formula - Ca(OH)
2
. It is used in industrial
settings, such as sewage treatment,
paper production, construction, and food
processing. Calum (calcium carbonate):
Formula - CaCO
3
.
Q.31. Which element of Group 17 has
two isotopes of masses 35 and 37 amu
with average abundance of 75.77% and
24.23%, respectively?
SSC CGL 17/07/2023 (1st shift)
(a) Chlorine (b) lodine
(c) Fluorine (d) Astatine
Sol.31.(a) Chlorine. Element of Group 17
: The halogens are located on the left of
the noble gases on the periodic table.
These ?ve toxic, non-metallic elements
make up Group 17 of the periodic table
and consist of : ?uorine (9, F), chlorine
(17, Cl), bromine (35, Br), iodine (53, I),
and astatine (85, At).
Q.32. Which of the following are
metalloids?
SSC CGL 18/07/2023 (2nd shift)
(a) Boron, oxygen, aluminium
(b) Boron, mercury, iron
(c) Boron, silicon, antimony
(d) Aluminium, mercury, copper
Sol.32.(c) Boron, silicon, antimony.
Metalloids - Chemical elements whose
physical and chemical properties fall in
between the metal and non-metal
categories . Seven most widely
recognized metalloids - Boron,
germanium, silicon, antimony, arsenic,
tellurium and polonium.
Q.33. Which among the following alloys
is a combination of gold and silver?
SSC MTS 10/05/2023 (Evening)
(a) Bronze (b) Constantan
(c) Solder (d) Electrum
Sol.33.(d) Electrum . Some other alloys:
Steel (Carbon and Iron). Stainless steel -
(Iron with Chromium and Nickel). German
silver - (copper, zinc and nickel). Rose
Metal - (Bismuth , Lead and Tin). Gun
Metal - (Cu + Sn + Zn + Pb). Dutch metal-
(Cu and Zn). Constantan (Eureka) - Alloy
of 55% Copper and 45% Nickel. Solder - It
is made up of Tin and Lead.
Q.34. Which of the following is a non -
metal that can exist in different form?
SSC MTS 12/05/2023 (Morning)
(a) Mercury (b) Carbon
(c) Lithium (d) Potassium
Sol.34.(b) Carbon (C) . Atomic number -
6. Belongs to the 14th group. It is a
tetravalent which makes a chemical
bond with four electrons. Each form of
carbon is called an allotrope. Diamond
(an allotrope of carbon) is the hardest
natural substance known and has a very
high melting and boiling point. Graphite,
another allotrope of carbon, is a
conductor of electricity.
Q.35. What is the characteristic of
isotopes ?
SSC MTS 18/05/2023 (Afternoon)
(a) Same neutron and same proton
(b) Same atomic number and different
mass number
(c) Same atomic number and same mass
number
(d) Same neutron and different proton
Sol.35.(b) An example of a group of
isotopes is hydrogen-1 (protium),
hydrogen-2 (deuterium), and hydrogen-3
(tritium). Isodiaphers - They are atoms of
different elements that have the same
difference between the number of
protons and the number of neutrons.
Example : Carbon-12 and Nitrogen-14.
Q.36. Which of the following metals is
always a component in an amalgam?
SSC MTS 15/06/2023 (Morning)
(a) Strontium (b) Mercury
(c) Zinc (d) Aluminium
Sol.36.(b) Mercury. Amalgam is an alloy
of mercury with one or more metals. The
most common amalgam is dental
amalgam, which is used to ?ll cavities in
teeth. Dental amalgam is a mixture of
mercury, silver, tin, and copper.
Q.37. Oxides of ____ and ______ dissolve
in rain water and form acids which are
called acid rain.
SSC MTS 16/06/2023 (Afternoon)
(a) phosphorous, sulphur
(b) sulphur, nitrogen
(c) carbon dioxide, methane
(d) calcium, magnesium
Sol.37.(b) Sulphur, nitrogen. Acid Rain -
When the pH of the rain water drops
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Pinnacle Chemistry
Chemistry
Structure of Atom
Q.1. Identify whether the given
statements about ionisation energy are
correct or incorrect.
Statement A:
The ionisation energy of an atom is the
amount of energy that is required to
remove an electron from a mole of
atoms in the gas phase.
Statement B:
The ionisation energy increases from top
to bottom in groups and decreases from
left to right across a period.
SSC CPO 04/10/2023 (Afternoon)
(a) Only Statement B is correct
(b) Only Statement A is correct
(c) Both Statements A and B are correct
(d) Both Statements A and B are
incorrect
Sol.1.(b) Only Statement A is correct.
The ionization energy decreases from
top to bottom in groups, and increases
from left to right across a period. Thus,
helium has the largest ionization energy,
while Caesium has the lowest.
Q.2. In which year did Carl Anderson
discover a positively charged particle
called "positron' whose mass appears to
be equal to the mass of an electron?
SSC CHSL 07/08/2023 (3rd shift)
(a) 1912 (b) 1932 (c) 1922 (d) 1942
Sol.2.(b) 1932. Electron - J.J. Thomson
(1897). Proton - E. Rutherford. Neutron -
James Chadwick (1932).
Q.3. In which year did Niels Bohr propose
a theory for the hydrogen atom based on
the quantum theory that some physical
quantities take only discrete values?
SSC CHSL 09/08/2023 (1st shift)
(a) 1919 (b) 1921 (c) 1909 (d) 1913
Sol.3.(d) 1913. Niels Bohr received the
Nobel Prize in 1922 "for his services in
the investigation of the structure of
atoms and of the radiation emanating
from them" .
Q.4. Which are the four quantum
numbers for an electron present in 4f
orbital?
SSC CHSL 03/08/2023 (1st shift)
(a) n = 4, = 3, m = +1, s = + ??
1
2
(b) n = 3, = 2, m = - 2, s = + ??
1
2
(c) n = 4, = 4, m = - 4, s = - ??
1
2
(d) n = 4, = 3, m = +4, s = + ??
1
2
Sol.4.(a) n = 4, l = 3, m = + 1, s = + .
1
2
There are four quantum numbers:
Principal (n) - It refers to the electron
shell with the most electrons, giving the
electron's likely distance from the
nucleus. Azimuthal (l) - It is de?ned as
the determination of the shape of an
orbital. Magnetic (m) - The subshell's
overall number of orbitals and their
orientation. Spin (s) - The values of n, l,
and m
l
have no bearing on the electron.
The 4s subshell contains 1 orbital and
can hold up to 2 electrons. The 4p
subshell contains 3 orbitals and can hold
up to 6 electrons. The 4d subshell
contains 5 orbitals and can hold up to 10
electrons.The 4f subshell has 7 orbitals
and can hold up to 14 electrons.
Q.5. The correct electronic con?guration
of Cu is :
SSC CHSL 07/08/2023 (1st shift)
(a) [Ar]3d
9
4s
2
(b) [Kr]3d
9
4s
2
(c) [Kr]3d
10
4s
1
(d) [Ar]3d
10
4s
1
Sol.5.(d) [Ar]3d
10
4s
1
. Copper (Cu) -
Atomic number (29), Electronic
con?guration - 1s² 2s² 2p6 3s² 3p6 4s¹
3d
10
or [Ar]3d
10
4s
1
.
Q.6. What does it mean when an object
has a positive charge ?
SSC MTS 19/05/2023 (Morning)
(a) It has more electrons than protons
(b) It has more protons than electrons
(c) It has more neutrons than electrons
(d) It has more neutrons than protons
Sol.6.(b) An electron is negatively
charged particle and protons are
positively charged particles.
Q.7. What is the relative charge of a
proton and neutron?
SSC MTS 15/06/2023 (Afternoon)
(a) -1 and +1 respectively
(b) +1 and -1 respectively
(c) +1 and 0 respectively
(d) -1 and 0 respectively
Sol.7.(c) +1 and 0 respectively.
Q.8. Which of the following pairs of
'number - composition' is correct?
I. Atomic number - number of protons
II. Mass number - Sum of number of
neutrons and protons
SSC CHSL 09/03/2023 (4th Shift)
(a) Only I (b) Neither I nor II
(c) Both I and II (d) Only II
Sol.8.(c) Both I and II. As atomic number
increases, subsequently mass number
also increases.
Q.9. What is the atomic mass of sodium?
SSC CHSL 13/03/2023 (1st Shift)
(a) 32 (b) 40 (c) 23 (d) 12
Sol.9.(c) 23. Sodium (Na) is an alkali
metal. Atomic number - 11, Group - 1 and
Period - 3, Sodium is a solid at room
temperature. Uses - Soaps, the puri?cation
of molten metals and sodium vapour
lamps.
Q.10. Which of the following is the
correct representation of number of
atoms?
SSC CHSL 14/03/2023 (4th Shift)
(a) ( ) ×
?????????? ????????
?????????? ????????
???????????????? ????????????
(b) ( ) ×
???????????????? ????????????
?????????? ????????
?????????? ????????
(c) ( ) ×
?????????? ????????
?????????? ????????
???????????????? ????????????
(d) ( ) ×
?????????? ????????
???????????????? ????????????
?????????? ????????
Sol.10.(a) ( ) × Avogadro
?????????? ????????
?????????? ????????
number . Avogadro number: 6.022 × 10²³.
Molar mass of a substance is the mass
(in grams) of one mole of the compound.
Q.11. What is the maximum number of
electrons that the third orbit or M-shell
can have?
SSC CHSL 21/03/2023 (2nd Shift)
(a) 32 (b) 8 (c) 18 (d) 2
Sol.11.(c) 18 . The maximum number of
electrons accommodated in a shell
based on principal quantum number (n).
It is represented by the formula 2n
2
.
K shell, n = 1, Max Electron = 2 × 1
2
= 2.
L shell, n = 2, Max Electron = 2 × 2
2
= 8.
M shell, n = 3, Max Electron = 2 × 3
2
= 18.
N shell, n = 4, Max Electron = 2 × 4
2
= 32.
Q.12. Which of the following statements
is NOT correct regarding Rutherford's
nuclear model of an atom?
SSC CHSL 21/03/2023 (2nd Shift)
(a) The size of the nucleus is very large
as compared to the size of the atom.
(b) The electrons revolve around the
nucleus in circular paths.
(c) There is a positively charged centre in
an atom called the nucleus.
(d) Nearly all the mass of an atom
resides in the nucleus.
Sol.12.(a) According to Rutherford’s
nuclear model of an atom, nucleus is
very small in size as compared to the
size of the atom. Rutherford explained
the revolving of electrons around the
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nucleus, however, he did not mention
how the electrons were placed inside,
which ended up making Rutherford’s
model an incomplete model of the atom.
Q.13. Which of the following pairs of
'elements - valency' is correct?
I. Boron - 2
II. Fluorine - 3
SSC CHSL 21/03/2023 (4th Shift)
(a) Neither I nor II (b) Both I and II
(c) Only II (d) Only I
Sol.13.(a) Neither I nor II. Valency -
Combining power of an element. Valency
of some elements : Aluminium (+3), Boron
(+3), ?uorine (-1).
Q.14. Which theory discusses the
relationship between ligand bonding and
degradation of d orbitals in metal
complexes and the geometry of metal
complexes and the splitting of d orbitals?
SSC CGL 05/12/2022 (4th Shift)
(a) Crystal ?eld theory (CFT)
(b) Ligand ?eld theory (LFT)
(c) Valence bond theory (VBT)
(d) Molecular orbital theory (MOT)
Sol.14.(a) Crystal ?eld theory: (1929,
developed by physicist Hans Bethe)
describes the breaking of orbital
degeneracy in transition metal
complexes due to the presence of
ligands.
Q.15. What kind of forces arise from
transient dipoles in atoms that induce
transient dipoles in nearby atoms,
produce an attractive force and are
signi?cant only over short distances
(~500 pm) ?
SSC CGL 02/12/2022 (1st Shift)
(a) Dipole-dipole forces
(b) London dispersion forces
(c) Dipole-induced dipole forces
(d) Hydrogen bond
Sol.15.(b) London Dispersion forces.
Dipole – Dipole Force is a form of
intermolecular force that occurs when a
polar molecule interacts with a non-polar
molecule . Dipole-induced dipole force is
a type of attractive force that operates
between the polar molecules having
permanent dipole and the molecules
lacking permanent dipole.
Q.16. In 1898, whose theory propounded
that the ions/groups bonded to the metal
by secondary bonding have spatial
arrangements corresponding to different
characteristics coordination number?
SSC CPO 09/11/2022 (Afternoon)
(a) Henry Taube (b) Alfred Werner
(c) Erich Huckel (d) Emil Fischer
Sol.16.(b) Alfred Werner. Nobel Prize for
Chemistry (1913). Henry Taube - Nobel
Prize in Chemistry (1983 - “for his studies
of the mechanisms of electron transfer in
metal complexes”).
Q.17. What is the atomicity of
Phosphorus?
SSC CPO 10/11/2022 (Evening)
(a) Poly-atomic (b) Monoatomic
(c) Diatomic (d) Tetra-atomic
Sol.17.(d) Tetra-atomic. Atomicity is the
total number of atoms present in a
molecule. Polyatomic (composed of
three or more atoms). Phosphorus was
?rst made by Hennig Brandt in 1669.
Q.18. Which formula is used to represent
the three-dimensional structures of
molecules using a two-dimensional
surface like a sheet of paper or a
computer screen?
SSC CPO 11/11/2022 (Evening)
(a) Bond-line formula
(b) Lewis structure formula
(c) Dash-wedge formula
(d) Condensed structural formula
Sol.18.(c) Dash-wedge formula. Bond -
line formula is used for every bond
represented as a line in a zigzag manner.
Q.19. In the electronic con?guration of
an atom, What does ‘n’ signify in the
formula 2n
2
?
SSC CHSL 27/05/2022 (Afternoon)
(a) The number of electrons
(b) The number of protons
(c) The number of the given shell from
the nucleus
(d) The number of valence electrons
present
Sol.19.(c) The electronic con?guration of
an element describes how electrons are
distributed in its atomic orbitals. The
maximum number of electrons that can
be accommodated in a shell is based on
the principal quantum number (n) and is
represented by the formula 2n
2
, where 'n'
is the shell number.
Q.20. According to Dalton’s atomic
theory, atoms combine in the ratio of
small whole numbers to form ______.
SSC MTS 2/11/2021 (Morning)
(a) neutrons (b) molecules
(c) protons (d) compounds
Sol.20.(d) Compounds . John Dalton is
considered the ‘Father of Modern Atomic
Theory’. Dalton's atomic theory (1808)
was the ?rst complete attempt to
describe all matter in terms of atoms and
their properties.
Q.21. If the size of the nucleus of an
atom is compared with a cricket ball,
then the radius of the atom is
approximately equal to how many
kilometers?
SSC CPO 23/11/2020 (Morning)
(a) 5 (b) 0.5 (c) 0.05 (d) 0.005
Sol.21.(a) 5 km. The radius of the atom
is 10
-10
m, and the radius of nucleus is
10
-15
m.
Q.22. The ?rst electron shell which is the
nearest to the nucleus never holds more
than 'n' electrons, where 'n' is equal to:
SSC CGL 6/03/2020 (Afternoon)
(a) 2 (b) 8 (c) 4 (d) 6
Sol.22.(a) 2. The maximum number of
electrons accommodated in a shell
based on principal quantum number (n).
It is represented by the formula 2n
2
.
K shell, n = 1, Max Electron = 2 × 1
2
= 2.
L shell, n = 2, Max Electron = 2 × 2
2
= 8.
M shell, n = 3, Max Electron = 2 × 3
2
= 18.
N shell, n = 4, Max Electron = 2 × 4
2
= 32.
Metals, Non-metals and Alloys
Q.23. Which of the following is NOT an
alkaline earth metal?
SSC Stenographer 12/10/2023 (Morning)
(a) Na (b) Mg (c) Ca (d) Be
Sol.23.(a) Na (Sodium) - It is an Alkali
metal. Alkaline earth metals: Beryllium
(Be, 4), Magnesium (Mg, 12), Calcium
(Ca, 20), Strontium (Sr, 38), Barium (Ba,
56), Radium (Ra, 88). They have two
electrons in their outermost shells. Alkali
metals: Lithium (Li, 3), Sodium (Na, 11),
Potassium (K, 19), Rubidium (Rb, 37),
Caesium (Cs, 55), Francium (Fr, 87).
Q.24. What is the name of the seventh
most abundant metal in the earth's crust,
which is derived from the medieval Latin
word 'Kalium' ?
SSC MTS 01/09/2023 (1st Shift)
(a) Aluminium (b) Magnesium
(c) Calcium (d) Potassium
Sol.24.(d) Potassium. It makes up 2.4%
by mass of the Earth crust. Aluminium is
the most abundant metal and Oxygen is
the most abundant non-metal found in
the earth's crust. Eight most abundant
elements in the Earth's crust are Oxygen
(O), Silicon (Si), Aluminium (Al), Calcium
(Ca), Iron (Fe), Magnesium (Mg), Sodium
(Na), and Potassium (K).
Q.25. Which chemical element with
atomic number 35 has a dark
reddish-brown liquid with a burning
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pungent odour ?
SSC MTS 06/09/2023 (1st Shift)
(a) Tennessine (b) Chlorine
(c) Astatine (d) Bromine
Sol.25.(d) Bromine (Br) is the third
halogen, a nonmetal in group 17 of the
periodic table. Products containing
bromine used in agriculture and
sanitation and as ?re retardants.
Q.26. An image of which of the following
elements is shown by the map of Cyprus
from which the element got its name ?
SSC MTS 13/09/2023 (2nd Shift)
(a) Silver (b) Cobalt
(c) Copper (d) Sulphur
Sol.26.(c) Copper (Cu, Atomic no 29). It
is a good conductor of heat and
electricity. It is in group 11, period 4 and
block ‘d’ of the periodic table. It was the
?rst metal used by man on earth.
Q.27. Which radioactive isotope has a
half-life of 5770 years, which is
commonly used to estimate the age of
organic materials such as paper and
parchment ?
SSC CHSL 08/08/2023 (1st shift)
(a)
9
C (b)
12
C (c)
14
C (d)
17
C
Sol.27.(c)
14
C - It is an unstable and
weakly radioactive isotope of carbon.
Three Natural isotopes of carbon :
12
C,
13
C and
14
C. Isotopes - Atoms of the
same element having the same atomic
number but different mass numbers. For
example, take the case of hydrogen
atom, it has three atomic species,
namely protium (
1
1
H), deuterium (
2
1
H or
D) and tritium (
3
1
H or T). The atomic
number of each one is 1, but the mass
number is 1, 2 and 3, respectively.
Q.28. Which metal ion released from the
tannery industry causes acute water
pollution?
SSC CHSL 09/08/2023 (1st shift)
(a) Mg (b) As (c) Cr (d) Zn
Sol.28.(c) Chromium (Cr). Tannery
Wastewaters: It contains Hairs, proteins,
acids, alkalis, chromium salts, sulphides,
chlorides, tannins, solvents, dyes.
Q.29. What is the most stable mineral
during the process of weathering?
SSC CHSL 10/08/2023 (1st shift)
(a) Quartz (b) Olivine
(c) Pyroxene (d) Amphibole
Sol.29.(a) Quartz (felsic mineral). Iron
oxides, Al-hydroxides, clay minerals and
quartz are the most stable weathered
products whereas highly soluble
minerals like halite are the least stable.
Silicates fall within the middle range.
Ma?c silicates like olivine, pyroxene or
amphibole breakdown relatively easily.
Weathering - The breaking down or
dissolving of rocks and minerals on
Earth's surface. Types of weathering:
Chemical, Physical and Biological
Weathering.
Q.30. From which Latin word is the s
block element calcium derived?
SSC CGL 14/07/2023 (3rd shift)
(a) Calx (b) Calum (c) Coleus (d) Calcio
Sol.30.(a) Calx (calcium hydroxide) .
Formula - Ca(OH)
2
. It is used in industrial
settings, such as sewage treatment,
paper production, construction, and food
processing. Calum (calcium carbonate):
Formula - CaCO
3
.
Q.31. Which element of Group 17 has
two isotopes of masses 35 and 37 amu
with average abundance of 75.77% and
24.23%, respectively?
SSC CGL 17/07/2023 (1st shift)
(a) Chlorine (b) lodine
(c) Fluorine (d) Astatine
Sol.31.(a) Chlorine. Element of Group 17
: The halogens are located on the left of
the noble gases on the periodic table.
These ?ve toxic, non-metallic elements
make up Group 17 of the periodic table
and consist of : ?uorine (9, F), chlorine
(17, Cl), bromine (35, Br), iodine (53, I),
and astatine (85, At).
Q.32. Which of the following are
metalloids?
SSC CGL 18/07/2023 (2nd shift)
(a) Boron, oxygen, aluminium
(b) Boron, mercury, iron
(c) Boron, silicon, antimony
(d) Aluminium, mercury, copper
Sol.32.(c) Boron, silicon, antimony.
Metalloids - Chemical elements whose
physical and chemical properties fall in
between the metal and non-metal
categories . Seven most widely
recognized metalloids - Boron,
germanium, silicon, antimony, arsenic,
tellurium and polonium.
Q.33. Which among the following alloys
is a combination of gold and silver?
SSC MTS 10/05/2023 (Evening)
(a) Bronze (b) Constantan
(c) Solder (d) Electrum
Sol.33.(d) Electrum . Some other alloys:
Steel (Carbon and Iron). Stainless steel -
(Iron with Chromium and Nickel). German
silver - (copper, zinc and nickel). Rose
Metal - (Bismuth , Lead and Tin). Gun
Metal - (Cu + Sn + Zn + Pb). Dutch metal-
(Cu and Zn). Constantan (Eureka) - Alloy
of 55% Copper and 45% Nickel. Solder - It
is made up of Tin and Lead.
Q.34. Which of the following is a non -
metal that can exist in different form?
SSC MTS 12/05/2023 (Morning)
(a) Mercury (b) Carbon
(c) Lithium (d) Potassium
Sol.34.(b) Carbon (C) . Atomic number -
6. Belongs to the 14th group. It is a
tetravalent which makes a chemical
bond with four electrons. Each form of
carbon is called an allotrope. Diamond
(an allotrope of carbon) is the hardest
natural substance known and has a very
high melting and boiling point. Graphite,
another allotrope of carbon, is a
conductor of electricity.
Q.35. What is the characteristic of
isotopes ?
SSC MTS 18/05/2023 (Afternoon)
(a) Same neutron and same proton
(b) Same atomic number and different
mass number
(c) Same atomic number and same mass
number
(d) Same neutron and different proton
Sol.35.(b) An example of a group of
isotopes is hydrogen-1 (protium),
hydrogen-2 (deuterium), and hydrogen-3
(tritium). Isodiaphers - They are atoms of
different elements that have the same
difference between the number of
protons and the number of neutrons.
Example : Carbon-12 and Nitrogen-14.
Q.36. Which of the following metals is
always a component in an amalgam?
SSC MTS 15/06/2023 (Morning)
(a) Strontium (b) Mercury
(c) Zinc (d) Aluminium
Sol.36.(b) Mercury. Amalgam is an alloy
of mercury with one or more metals. The
most common amalgam is dental
amalgam, which is used to ?ll cavities in
teeth. Dental amalgam is a mixture of
mercury, silver, tin, and copper.
Q.37. Oxides of ____ and ______ dissolve
in rain water and form acids which are
called acid rain.
SSC MTS 16/06/2023 (Afternoon)
(a) phosphorous, sulphur
(b) sulphur, nitrogen
(c) carbon dioxide, methane
(d) calcium, magnesium
Sol.37.(b) Sulphur, nitrogen. Acid Rain -
When the pH of the rain water drops
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below 5.6, it is called acid rain. Acid rain
damages buildings and other structures
made of stone or metal. The main reason
for this is air pollution caused by the
burning of fossil fuels. The Taj Mahal has
been affected by acid rain.
Q.38. Which among the following alloys
is made up of copper and zinc?
SSC CHSL 13/03/2023 (3rd Shift)
(a) Monel Metal (b) Magnalium
(c) Rolled Gold (d) Dutch Metal
Sol.38.(d) Dutch Metal. Monel metal:
Group of alloys of Copper and Nickel.
Uses: marine engineering, chemical and
hydrocarbon processing equipment,
valves, pumps, shafts, ?ttings, fasteners,
and heat exchangers, Magnalium:
Mixture of magnesium and aluminium,
used in making aircrafts and automobile
parts, Rolled gold: An alloy of Copper
and Aluminium, used for making cheap
ornaments.
Q.39. Which of the following statements
is correct ?
SSC CHSL 14/03/2023 (3rd Shift)
(a) Metals react with acids and produce
metal salts and hydrogen gas.
(b) Non - metals react with oxygen to
produce non - metallic oxides which
are basic in nature.
(c) On burning, metals react with oxygen
to produce metal oxides which are
acidic in nature.
(d) Less reactive metals displace more
reactive metals from their compounds
in aqueous solutions.
Sol.39.(a) Example - Fe (Iron) + H
2
SO
4
(sulfuric acid) ? FeSO
4
(ferrous sulfate)
+ H
2
(hydrogen). Non - metals react with
oxygen - produce nonmetallic oxides
(Acidic), Example - S (Sulphur) + O
2
(Oxygen) ? SO
2
(Sulphur Dioxide).
Metals react with oxygen - Produce
metallic oxides (Basic) , Example - Mg
(Magnesium) + O
2
(Oxygen) ? MgO
(Magnesium Oxide).
Q.40. Which of the following statements
is/are NOT correct ?
I. The property of metals by which they
can be beaten into thin sheets is called
malleability.
II. The property of metal by which it can
being drawn into wires is called ductility.
SSC CHSL 21/03/2023 (4th Shift)
(a) Neither I nor II (b) Both I and II
(c) Only I (d) Only II
Sol.40.(a) Neither I nor II . Malleability -
The property of metals to be beaten into
thin sheets . Examples - Copper, silver.
Ductility - The property of metal to be
drawn into wires. Examples - Gold, silver
and copper. Density and melting point of
metals is high.
Q.41. Which of the following liquids can
dissolve noble metals such as gold and
platinum?
SSC CPO 10/11/2022 (Afternoon)
(a) Formic acid (b) Aqua regia
(c) Acetic acid (d) Chloroform
Sol.41.(b) Aqua regia is a mixture of
hydrochloric acid and nitric acid present
in the ratio 3:1. Formic acid (methanoic
acid, chemical formula - HCOOH ) is the
simplest carboxylic acid ,used as a
preservative and antibacterial agent.
Q.42. Which of the following statements
is NOT correct regarding the alkali
metals?
SSC CPO 11/11/2022 (Afternoon)
(a) All the alkali metals are silvery white,
soft and light metals.
(b) The ionization enthalpies of the alkali
metals are considerably low and
decrease down the group from.
(c) Group 1 metals are known as alkali
metals.
(d) All the alkali metals have two valence
electrons.
Sol.42.(d) Alkali metals have one
electron in their valence shell. Group 1A
of the periodic table are the alkali metals:
Hydrogen (H, 1), Lithium (Li, 3), Sodium
(Na, 11), Potassium (K , 19), Rubidium
(Rb, 37), Cesium (Cs, 55), and Francium
(Fr , 87).
Q.43. Which of the following statements
is INCORRECT?
SSC MTS 11/07/2022 (Morning)
(a) Metals are used in making cookware.
(b) Metals are used in the manufacture
of automobiles.
(c) Living beings inhale metals during
respiration.
(d) Metals are used in manufacturing
jewellery.
Sol.43.(c) Living beings do not inhale
metals during respiration. Humans get
the oxygen they need by breathing
through their nose and mouth into their
lungs. Normal respiration rates for an
adult person at rest range from 12 to 16
breaths per minute.
Q.44. Choose the most reactive metal
from the options given below.
SSC MTS 06/07/2022 (Evening)
(a) Copper (b) Zinc (c) Sodium (d) Iron
Sol.44.(c) Sodium. Reactive metals in
order: Potassium (Most reactive metal),
Sodium, Barium, Calcium, Magnesium,
Aluminium, Zinc, Iron, Nickel, Tin, Lead,
Hydrogen, Copper, Mercury, Silver, Gold,
Platinum (Least Reactive).
Q.45. Which of the following statements
is INCORRECT ?
SSC MTS 15/07/2022 (Afternoon)
(a) Metals react with oxygen to form
basic oxides.
(b) Non-metals are malleable
(c) Non-metals do not produce any sound
(d) Metals have low ionisation enthalpy
Sol.45.(b) Physical Properties of Non
metals: Poor conductors of electricity
and heat, Non-malleable nor ductile,
Brittle solids, May be solids, liquids, or
gases at room temperature, These are
not sonorous, and Transparent.
Q.46. Which of the following metals
reacts violently with cold water?
SSC MTS 25/07/2022 (Afternoon)
(a) Magnesium (b) Aluminium
(c) Zinc (d) Potassium
Sol.46.(d) Potassium and sodium react
violently with cold water, where sodium
reacts slightly stronger than Potassium.
The reaction is exothermic in nature and
in each reaction, hydrogen gas is given
off and the metal hydroxide is produced.
Q.47. Which of the following metals
having atomic number 3 is a soft, silvery
metal with very low density that reacts
vigorously with water and corrodes
quickly in air?
SSC CHSL 24/05/2022 (Morning)
(a) Potassium (b) Sodium
(c) Lithium (d) Rubidium
Sol.47.(c) Lithium. It has the lowest
density of all metals. Lithium is the ?rst
of the alkalis metals in the periodic table.
It is highly reactive and does not occur
freely in nature. Lithium is the only alkali
metal that reacts with nitrogen.
Q.48. Identify the INCORRECT pair with
respect to the substances and their
speci?c heat capacity (J ) at ????
- 1
??
- 1
room temperature and atmospheric
pressure.
SSC CHSL 26/05/2022 (Afternoon)
(a) Aluminium – 900.0
(b) Water – 1200
(c) Carbon – 506.5
(d) Tungsten – 134.4
Sol.48.(b) Water has a speci?c heat
capacity of 4186 Jkg
-1
K
-1
. Speci?c heat
of some substance- Iron/Steel- 450,
Copper- 390, Silver- 230, Mercury- 140,
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Chemistry
Structure of Atom
Q.1. Identify whether the given
statements about ionisation energy are
correct or incorrect.
Statement A:
The ionisation energy of an atom is the
amount of energy that is required to
remove an electron from a mole of
atoms in the gas phase.
Statement B:
The ionisation energy increases from top
to bottom in groups and decreases from
left to right across a period.
SSC CPO 04/10/2023 (Afternoon)
(a) Only Statement B is correct
(b) Only Statement A is correct
(c) Both Statements A and B are correct
(d) Both Statements A and B are
incorrect
Sol.1.(b) Only Statement A is correct.
The ionization energy decreases from
top to bottom in groups, and increases
from left to right across a period. Thus,
helium has the largest ionization energy,
while Caesium has the lowest.
Q.2. In which year did Carl Anderson
discover a positively charged particle
called "positron' whose mass appears to
be equal to the mass of an electron?
SSC CHSL 07/08/2023 (3rd shift)
(a) 1912 (b) 1932 (c) 1922 (d) 1942
Sol.2.(b) 1932. Electron - J.J. Thomson
(1897). Proton - E. Rutherford. Neutron -
James Chadwick (1932).
Q.3. In which year did Niels Bohr propose
a theory for the hydrogen atom based on
the quantum theory that some physical
quantities take only discrete values?
SSC CHSL 09/08/2023 (1st shift)
(a) 1919 (b) 1921 (c) 1909 (d) 1913
Sol.3.(d) 1913. Niels Bohr received the
Nobel Prize in 1922 "for his services in
the investigation of the structure of
atoms and of the radiation emanating
from them" .
Q.4. Which are the four quantum
numbers for an electron present in 4f
orbital?
SSC CHSL 03/08/2023 (1st shift)
(a) n = 4, = 3, m = +1, s = + ??
1
2
(b) n = 3, = 2, m = - 2, s = + ??
1
2
(c) n = 4, = 4, m = - 4, s = - ??
1
2
(d) n = 4, = 3, m = +4, s = + ??
1
2
Sol.4.(a) n = 4, l = 3, m = + 1, s = + .
1
2
There are four quantum numbers:
Principal (n) - It refers to the electron
shell with the most electrons, giving the
electron's likely distance from the
nucleus. Azimuthal (l) - It is de?ned as
the determination of the shape of an
orbital. Magnetic (m) - The subshell's
overall number of orbitals and their
orientation. Spin (s) - The values of n, l,
and m
l
have no bearing on the electron.
The 4s subshell contains 1 orbital and
can hold up to 2 electrons. The 4p
subshell contains 3 orbitals and can hold
up to 6 electrons. The 4d subshell
contains 5 orbitals and can hold up to 10
electrons.The 4f subshell has 7 orbitals
and can hold up to 14 electrons.
Q.5. The correct electronic con?guration
of Cu is :
SSC CHSL 07/08/2023 (1st shift)
(a) [Ar]3d
9
4s
2
(b) [Kr]3d
9
4s
2
(c) [Kr]3d
10
4s
1
(d) [Ar]3d
10
4s
1
Sol.5.(d) [Ar]3d
10
4s
1
. Copper (Cu) -
Atomic number (29), Electronic
con?guration - 1s² 2s² 2p6 3s² 3p6 4s¹
3d
10
or [Ar]3d
10
4s
1
.
Q.6. What does it mean when an object
has a positive charge ?
SSC MTS 19/05/2023 (Morning)
(a) It has more electrons than protons
(b) It has more protons than electrons
(c) It has more neutrons than electrons
(d) It has more neutrons than protons
Sol.6.(b) An electron is negatively
charged particle and protons are
positively charged particles.
Q.7. What is the relative charge of a
proton and neutron?
SSC MTS 15/06/2023 (Afternoon)
(a) -1 and +1 respectively
(b) +1 and -1 respectively
(c) +1 and 0 respectively
(d) -1 and 0 respectively
Sol.7.(c) +1 and 0 respectively.
Q.8. Which of the following pairs of
'number - composition' is correct?
I. Atomic number - number of protons
II. Mass number - Sum of number of
neutrons and protons
SSC CHSL 09/03/2023 (4th Shift)
(a) Only I (b) Neither I nor II
(c) Both I and II (d) Only II
Sol.8.(c) Both I and II. As atomic number
increases, subsequently mass number
also increases.
Q.9. What is the atomic mass of sodium?
SSC CHSL 13/03/2023 (1st Shift)
(a) 32 (b) 40 (c) 23 (d) 12
Sol.9.(c) 23. Sodium (Na) is an alkali
metal. Atomic number - 11, Group - 1 and
Period - 3, Sodium is a solid at room
temperature. Uses - Soaps, the puri?cation
of molten metals and sodium vapour
lamps.
Q.10. Which of the following is the
correct representation of number of
atoms?
SSC CHSL 14/03/2023 (4th Shift)
(a) ( ) ×
?????????? ????????
?????????? ????????
???????????????? ????????????
(b) ( ) ×
???????????????? ????????????
?????????? ????????
?????????? ????????
(c) ( ) ×
?????????? ????????
?????????? ????????
???????????????? ????????????
(d) ( ) ×
?????????? ????????
???????????????? ????????????
?????????? ????????
Sol.10.(a) ( ) × Avogadro
?????????? ????????
?????????? ????????
number . Avogadro number: 6.022 × 10²³.
Molar mass of a substance is the mass
(in grams) of one mole of the compound.
Q.11. What is the maximum number of
electrons that the third orbit or M-shell
can have?
SSC CHSL 21/03/2023 (2nd Shift)
(a) 32 (b) 8 (c) 18 (d) 2
Sol.11.(c) 18 . The maximum number of
electrons accommodated in a shell
based on principal quantum number (n).
It is represented by the formula 2n
2
.
K shell, n = 1, Max Electron = 2 × 1
2
= 2.
L shell, n = 2, Max Electron = 2 × 2
2
= 8.
M shell, n = 3, Max Electron = 2 × 3
2
= 18.
N shell, n = 4, Max Electron = 2 × 4
2
= 32.
Q.12. Which of the following statements
is NOT correct regarding Rutherford's
nuclear model of an atom?
SSC CHSL 21/03/2023 (2nd Shift)
(a) The size of the nucleus is very large
as compared to the size of the atom.
(b) The electrons revolve around the
nucleus in circular paths.
(c) There is a positively charged centre in
an atom called the nucleus.
(d) Nearly all the mass of an atom
resides in the nucleus.
Sol.12.(a) According to Rutherford’s
nuclear model of an atom, nucleus is
very small in size as compared to the
size of the atom. Rutherford explained
the revolving of electrons around the
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nucleus, however, he did not mention
how the electrons were placed inside,
which ended up making Rutherford’s
model an incomplete model of the atom.
Q.13. Which of the following pairs of
'elements - valency' is correct?
I. Boron - 2
II. Fluorine - 3
SSC CHSL 21/03/2023 (4th Shift)
(a) Neither I nor II (b) Both I and II
(c) Only II (d) Only I
Sol.13.(a) Neither I nor II. Valency -
Combining power of an element. Valency
of some elements : Aluminium (+3), Boron
(+3), ?uorine (-1).
Q.14. Which theory discusses the
relationship between ligand bonding and
degradation of d orbitals in metal
complexes and the geometry of metal
complexes and the splitting of d orbitals?
SSC CGL 05/12/2022 (4th Shift)
(a) Crystal ?eld theory (CFT)
(b) Ligand ?eld theory (LFT)
(c) Valence bond theory (VBT)
(d) Molecular orbital theory (MOT)
Sol.14.(a) Crystal ?eld theory: (1929,
developed by physicist Hans Bethe)
describes the breaking of orbital
degeneracy in transition metal
complexes due to the presence of
ligands.
Q.15. What kind of forces arise from
transient dipoles in atoms that induce
transient dipoles in nearby atoms,
produce an attractive force and are
signi?cant only over short distances
(~500 pm) ?
SSC CGL 02/12/2022 (1st Shift)
(a) Dipole-dipole forces
(b) London dispersion forces
(c) Dipole-induced dipole forces
(d) Hydrogen bond
Sol.15.(b) London Dispersion forces.
Dipole – Dipole Force is a form of
intermolecular force that occurs when a
polar molecule interacts with a non-polar
molecule . Dipole-induced dipole force is
a type of attractive force that operates
between the polar molecules having
permanent dipole and the molecules
lacking permanent dipole.
Q.16. In 1898, whose theory propounded
that the ions/groups bonded to the metal
by secondary bonding have spatial
arrangements corresponding to different
characteristics coordination number?
SSC CPO 09/11/2022 (Afternoon)
(a) Henry Taube (b) Alfred Werner
(c) Erich Huckel (d) Emil Fischer
Sol.16.(b) Alfred Werner. Nobel Prize for
Chemistry (1913). Henry Taube - Nobel
Prize in Chemistry (1983 - “for his studies
of the mechanisms of electron transfer in
metal complexes”).
Q.17. What is the atomicity of
Phosphorus?
SSC CPO 10/11/2022 (Evening)
(a) Poly-atomic (b) Monoatomic
(c) Diatomic (d) Tetra-atomic
Sol.17.(d) Tetra-atomic. Atomicity is the
total number of atoms present in a
molecule. Polyatomic (composed of
three or more atoms). Phosphorus was
?rst made by Hennig Brandt in 1669.
Q.18. Which formula is used to represent
the three-dimensional structures of
molecules using a two-dimensional
surface like a sheet of paper or a
computer screen?
SSC CPO 11/11/2022 (Evening)
(a) Bond-line formula
(b) Lewis structure formula
(c) Dash-wedge formula
(d) Condensed structural formula
Sol.18.(c) Dash-wedge formula. Bond -
line formula is used for every bond
represented as a line in a zigzag manner.
Q.19. In the electronic con?guration of
an atom, What does ‘n’ signify in the
formula 2n
2
?
SSC CHSL 27/05/2022 (Afternoon)
(a) The number of electrons
(b) The number of protons
(c) The number of the given shell from
the nucleus
(d) The number of valence electrons
present
Sol.19.(c) The electronic con?guration of
an element describes how electrons are
distributed in its atomic orbitals. The
maximum number of electrons that can
be accommodated in a shell is based on
the principal quantum number (n) and is
represented by the formula 2n
2
, where 'n'
is the shell number.
Q.20. According to Dalton’s atomic
theory, atoms combine in the ratio of
small whole numbers to form ______.
SSC MTS 2/11/2021 (Morning)
(a) neutrons (b) molecules
(c) protons (d) compounds
Sol.20.(d) Compounds . John Dalton is
considered the ‘Father of Modern Atomic
Theory’. Dalton's atomic theory (1808)
was the ?rst complete attempt to
describe all matter in terms of atoms and
their properties.
Q.21. If the size of the nucleus of an
atom is compared with a cricket ball,
then the radius of the atom is
approximately equal to how many
kilometers?
SSC CPO 23/11/2020 (Morning)
(a) 5 (b) 0.5 (c) 0.05 (d) 0.005
Sol.21.(a) 5 km. The radius of the atom
is 10
-10
m, and the radius of nucleus is
10
-15
m.
Q.22. The ?rst electron shell which is the
nearest to the nucleus never holds more
than 'n' electrons, where 'n' is equal to:
SSC CGL 6/03/2020 (Afternoon)
(a) 2 (b) 8 (c) 4 (d) 6
Sol.22.(a) 2. The maximum number of
electrons accommodated in a shell
based on principal quantum number (n).
It is represented by the formula 2n
2
.
K shell, n = 1, Max Electron = 2 × 1
2
= 2.
L shell, n = 2, Max Electron = 2 × 2
2
= 8.
M shell, n = 3, Max Electron = 2 × 3
2
= 18.
N shell, n = 4, Max Electron = 2 × 4
2
= 32.
Metals, Non-metals and Alloys
Q.23. Which of the following is NOT an
alkaline earth metal?
SSC Stenographer 12/10/2023 (Morning)
(a) Na (b) Mg (c) Ca (d) Be
Sol.23.(a) Na (Sodium) - It is an Alkali
metal. Alkaline earth metals: Beryllium
(Be, 4), Magnesium (Mg, 12), Calcium
(Ca, 20), Strontium (Sr, 38), Barium (Ba,
56), Radium (Ra, 88). They have two
electrons in their outermost shells. Alkali
metals: Lithium (Li, 3), Sodium (Na, 11),
Potassium (K, 19), Rubidium (Rb, 37),
Caesium (Cs, 55), Francium (Fr, 87).
Q.24. What is the name of the seventh
most abundant metal in the earth's crust,
which is derived from the medieval Latin
word 'Kalium' ?
SSC MTS 01/09/2023 (1st Shift)
(a) Aluminium (b) Magnesium
(c) Calcium (d) Potassium
Sol.24.(d) Potassium. It makes up 2.4%
by mass of the Earth crust. Aluminium is
the most abundant metal and Oxygen is
the most abundant non-metal found in
the earth's crust. Eight most abundant
elements in the Earth's crust are Oxygen
(O), Silicon (Si), Aluminium (Al), Calcium
(Ca), Iron (Fe), Magnesium (Mg), Sodium
(Na), and Potassium (K).
Q.25. Which chemical element with
atomic number 35 has a dark
reddish-brown liquid with a burning
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pungent odour ?
SSC MTS 06/09/2023 (1st Shift)
(a) Tennessine (b) Chlorine
(c) Astatine (d) Bromine
Sol.25.(d) Bromine (Br) is the third
halogen, a nonmetal in group 17 of the
periodic table. Products containing
bromine used in agriculture and
sanitation and as ?re retardants.
Q.26. An image of which of the following
elements is shown by the map of Cyprus
from which the element got its name ?
SSC MTS 13/09/2023 (2nd Shift)
(a) Silver (b) Cobalt
(c) Copper (d) Sulphur
Sol.26.(c) Copper (Cu, Atomic no 29). It
is a good conductor of heat and
electricity. It is in group 11, period 4 and
block ‘d’ of the periodic table. It was the
?rst metal used by man on earth.
Q.27. Which radioactive isotope has a
half-life of 5770 years, which is
commonly used to estimate the age of
organic materials such as paper and
parchment ?
SSC CHSL 08/08/2023 (1st shift)
(a)
9
C (b)
12
C (c)
14
C (d)
17
C
Sol.27.(c)
14
C - It is an unstable and
weakly radioactive isotope of carbon.
Three Natural isotopes of carbon :
12
C,
13
C and
14
C. Isotopes - Atoms of the
same element having the same atomic
number but different mass numbers. For
example, take the case of hydrogen
atom, it has three atomic species,
namely protium (
1
1
H), deuterium (
2
1
H or
D) and tritium (
3
1
H or T). The atomic
number of each one is 1, but the mass
number is 1, 2 and 3, respectively.
Q.28. Which metal ion released from the
tannery industry causes acute water
pollution?
SSC CHSL 09/08/2023 (1st shift)
(a) Mg (b) As (c) Cr (d) Zn
Sol.28.(c) Chromium (Cr). Tannery
Wastewaters: It contains Hairs, proteins,
acids, alkalis, chromium salts, sulphides,
chlorides, tannins, solvents, dyes.
Q.29. What is the most stable mineral
during the process of weathering?
SSC CHSL 10/08/2023 (1st shift)
(a) Quartz (b) Olivine
(c) Pyroxene (d) Amphibole
Sol.29.(a) Quartz (felsic mineral). Iron
oxides, Al-hydroxides, clay minerals and
quartz are the most stable weathered
products whereas highly soluble
minerals like halite are the least stable.
Silicates fall within the middle range.
Ma?c silicates like olivine, pyroxene or
amphibole breakdown relatively easily.
Weathering - The breaking down or
dissolving of rocks and minerals on
Earth's surface. Types of weathering:
Chemical, Physical and Biological
Weathering.
Q.30. From which Latin word is the s
block element calcium derived?
SSC CGL 14/07/2023 (3rd shift)
(a) Calx (b) Calum (c) Coleus (d) Calcio
Sol.30.(a) Calx (calcium hydroxide) .
Formula - Ca(OH)
2
. It is used in industrial
settings, such as sewage treatment,
paper production, construction, and food
processing. Calum (calcium carbonate):
Formula - CaCO
3
.
Q.31. Which element of Group 17 has
two isotopes of masses 35 and 37 amu
with average abundance of 75.77% and
24.23%, respectively?
SSC CGL 17/07/2023 (1st shift)
(a) Chlorine (b) lodine
(c) Fluorine (d) Astatine
Sol.31.(a) Chlorine. Element of Group 17
: The halogens are located on the left of
the noble gases on the periodic table.
These ?ve toxic, non-metallic elements
make up Group 17 of the periodic table
and consist of : ?uorine (9, F), chlorine
(17, Cl), bromine (35, Br), iodine (53, I),
and astatine (85, At).
Q.32. Which of the following are
metalloids?
SSC CGL 18/07/2023 (2nd shift)
(a) Boron, oxygen, aluminium
(b) Boron, mercury, iron
(c) Boron, silicon, antimony
(d) Aluminium, mercury, copper
Sol.32.(c) Boron, silicon, antimony.
Metalloids - Chemical elements whose
physical and chemical properties fall in
between the metal and non-metal
categories . Seven most widely
recognized metalloids - Boron,
germanium, silicon, antimony, arsenic,
tellurium and polonium.
Q.33. Which among the following alloys
is a combination of gold and silver?
SSC MTS 10/05/2023 (Evening)
(a) Bronze (b) Constantan
(c) Solder (d) Electrum
Sol.33.(d) Electrum . Some other alloys:
Steel (Carbon and Iron). Stainless steel -
(Iron with Chromium and Nickel). German
silver - (copper, zinc and nickel). Rose
Metal - (Bismuth , Lead and Tin). Gun
Metal - (Cu + Sn + Zn + Pb). Dutch metal-
(Cu and Zn). Constantan (Eureka) - Alloy
of 55% Copper and 45% Nickel. Solder - It
is made up of Tin and Lead.
Q.34. Which of the following is a non -
metal that can exist in different form?
SSC MTS 12/05/2023 (Morning)
(a) Mercury (b) Carbon
(c) Lithium (d) Potassium
Sol.34.(b) Carbon (C) . Atomic number -
6. Belongs to the 14th group. It is a
tetravalent which makes a chemical
bond with four electrons. Each form of
carbon is called an allotrope. Diamond
(an allotrope of carbon) is the hardest
natural substance known and has a very
high melting and boiling point. Graphite,
another allotrope of carbon, is a
conductor of electricity.
Q.35. What is the characteristic of
isotopes ?
SSC MTS 18/05/2023 (Afternoon)
(a) Same neutron and same proton
(b) Same atomic number and different
mass number
(c) Same atomic number and same mass
number
(d) Same neutron and different proton
Sol.35.(b) An example of a group of
isotopes is hydrogen-1 (protium),
hydrogen-2 (deuterium), and hydrogen-3
(tritium). Isodiaphers - They are atoms of
different elements that have the same
difference between the number of
protons and the number of neutrons.
Example : Carbon-12 and Nitrogen-14.
Q.36. Which of the following metals is
always a component in an amalgam?
SSC MTS 15/06/2023 (Morning)
(a) Strontium (b) Mercury
(c) Zinc (d) Aluminium
Sol.36.(b) Mercury. Amalgam is an alloy
of mercury with one or more metals. The
most common amalgam is dental
amalgam, which is used to ?ll cavities in
teeth. Dental amalgam is a mixture of
mercury, silver, tin, and copper.
Q.37. Oxides of ____ and ______ dissolve
in rain water and form acids which are
called acid rain.
SSC MTS 16/06/2023 (Afternoon)
(a) phosphorous, sulphur
(b) sulphur, nitrogen
(c) carbon dioxide, methane
(d) calcium, magnesium
Sol.37.(b) Sulphur, nitrogen. Acid Rain -
When the pH of the rain water drops
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below 5.6, it is called acid rain. Acid rain
damages buildings and other structures
made of stone or metal. The main reason
for this is air pollution caused by the
burning of fossil fuels. The Taj Mahal has
been affected by acid rain.
Q.38. Which among the following alloys
is made up of copper and zinc?
SSC CHSL 13/03/2023 (3rd Shift)
(a) Monel Metal (b) Magnalium
(c) Rolled Gold (d) Dutch Metal
Sol.38.(d) Dutch Metal. Monel metal:
Group of alloys of Copper and Nickel.
Uses: marine engineering, chemical and
hydrocarbon processing equipment,
valves, pumps, shafts, ?ttings, fasteners,
and heat exchangers, Magnalium:
Mixture of magnesium and aluminium,
used in making aircrafts and automobile
parts, Rolled gold: An alloy of Copper
and Aluminium, used for making cheap
ornaments.
Q.39. Which of the following statements
is correct ?
SSC CHSL 14/03/2023 (3rd Shift)
(a) Metals react with acids and produce
metal salts and hydrogen gas.
(b) Non - metals react with oxygen to
produce non - metallic oxides which
are basic in nature.
(c) On burning, metals react with oxygen
to produce metal oxides which are
acidic in nature.
(d) Less reactive metals displace more
reactive metals from their compounds
in aqueous solutions.
Sol.39.(a) Example - Fe (Iron) + H
2
SO
4
(sulfuric acid) ? FeSO
4
(ferrous sulfate)
+ H
2
(hydrogen). Non - metals react with
oxygen - produce nonmetallic oxides
(Acidic), Example - S (Sulphur) + O
2
(Oxygen) ? SO
2
(Sulphur Dioxide).
Metals react with oxygen - Produce
metallic oxides (Basic) , Example - Mg
(Magnesium) + O
2
(Oxygen) ? MgO
(Magnesium Oxide).
Q.40. Which of the following statements
is/are NOT correct ?
I. The property of metals by which they
can be beaten into thin sheets is called
malleability.
II. The property of metal by which it can
being drawn into wires is called ductility.
SSC CHSL 21/03/2023 (4th Shift)
(a) Neither I nor II (b) Both I and II
(c) Only I (d) Only II
Sol.40.(a) Neither I nor II . Malleability -
The property of metals to be beaten into
thin sheets . Examples - Copper, silver.
Ductility - The property of metal to be
drawn into wires. Examples - Gold, silver
and copper. Density and melting point of
metals is high.
Q.41. Which of the following liquids can
dissolve noble metals such as gold and
platinum?
SSC CPO 10/11/2022 (Afternoon)
(a) Formic acid (b) Aqua regia
(c) Acetic acid (d) Chloroform
Sol.41.(b) Aqua regia is a mixture of
hydrochloric acid and nitric acid present
in the ratio 3:1. Formic acid (methanoic
acid, chemical formula - HCOOH ) is the
simplest carboxylic acid ,used as a
preservative and antibacterial agent.
Q.42. Which of the following statements
is NOT correct regarding the alkali
metals?
SSC CPO 11/11/2022 (Afternoon)
(a) All the alkali metals are silvery white,
soft and light metals.
(b) The ionization enthalpies of the alkali
metals are considerably low and
decrease down the group from.
(c) Group 1 metals are known as alkali
metals.
(d) All the alkali metals have two valence
electrons.
Sol.42.(d) Alkali metals have one
electron in their valence shell. Group 1A
of the periodic table are the alkali metals:
Hydrogen (H, 1), Lithium (Li, 3), Sodium
(Na, 11), Potassium (K , 19), Rubidium
(Rb, 37), Cesium (Cs, 55), and Francium
(Fr , 87).
Q.43. Which of the following statements
is INCORRECT?
SSC MTS 11/07/2022 (Morning)
(a) Metals are used in making cookware.
(b) Metals are used in the manufacture
of automobiles.
(c) Living beings inhale metals during
respiration.
(d) Metals are used in manufacturing
jewellery.
Sol.43.(c) Living beings do not inhale
metals during respiration. Humans get
the oxygen they need by breathing
through their nose and mouth into their
lungs. Normal respiration rates for an
adult person at rest range from 12 to 16
breaths per minute.
Q.44. Choose the most reactive metal
from the options given below.
SSC MTS 06/07/2022 (Evening)
(a) Copper (b) Zinc (c) Sodium (d) Iron
Sol.44.(c) Sodium. Reactive metals in
order: Potassium (Most reactive metal),
Sodium, Barium, Calcium, Magnesium,
Aluminium, Zinc, Iron, Nickel, Tin, Lead,
Hydrogen, Copper, Mercury, Silver, Gold,
Platinum (Least Reactive).
Q.45. Which of the following statements
is INCORRECT ?
SSC MTS 15/07/2022 (Afternoon)
(a) Metals react with oxygen to form
basic oxides.
(b) Non-metals are malleable
(c) Non-metals do not produce any sound
(d) Metals have low ionisation enthalpy
Sol.45.(b) Physical Properties of Non
metals: Poor conductors of electricity
and heat, Non-malleable nor ductile,
Brittle solids, May be solids, liquids, or
gases at room temperature, These are
not sonorous, and Transparent.
Q.46. Which of the following metals
reacts violently with cold water?
SSC MTS 25/07/2022 (Afternoon)
(a) Magnesium (b) Aluminium
(c) Zinc (d) Potassium
Sol.46.(d) Potassium and sodium react
violently with cold water, where sodium
reacts slightly stronger than Potassium.
The reaction is exothermic in nature and
in each reaction, hydrogen gas is given
off and the metal hydroxide is produced.
Q.47. Which of the following metals
having atomic number 3 is a soft, silvery
metal with very low density that reacts
vigorously with water and corrodes
quickly in air?
SSC CHSL 24/05/2022 (Morning)
(a) Potassium (b) Sodium
(c) Lithium (d) Rubidium
Sol.47.(c) Lithium. It has the lowest
density of all metals. Lithium is the ?rst
of the alkalis metals in the periodic table.
It is highly reactive and does not occur
freely in nature. Lithium is the only alkali
metal that reacts with nitrogen.
Q.48. Identify the INCORRECT pair with
respect to the substances and their
speci?c heat capacity (J ) at ????
- 1
??
- 1
room temperature and atmospheric
pressure.
SSC CHSL 26/05/2022 (Afternoon)
(a) Aluminium – 900.0
(b) Water – 1200
(c) Carbon – 506.5
(d) Tungsten – 134.4
Sol.48.(b) Water has a speci?c heat
capacity of 4186 Jkg
-1
K
-1
. Speci?c heat
of some substance- Iron/Steel- 450,
Copper- 390, Silver- 230, Mercury- 140,
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Platinum- 130, Hydrogen- 14000, Air- 718,
Ice- 2100, Sea Water- 3900 etc.
Q.49. The particles of which metal on
heating to the boiling point of 357°C go
from liquid state to gas state?
SSC CHSL 26/05/2022 (Afternoon)
(a) Mercury (b) Copper
(c) Bronze (d) Gallium
Sol.49.(a) Mercury (Hg, Atomic
Number-80) is also a good conductor of
electricity, so it is a useful component of
electrical switches. Mercury is also used
in dental ?llings, paints, soaps, batteries,
and ?uorescent lighting. It is commonly
known as quicksilver and was formerly
named hydrargyrum.
Q.50. The name of which element is
derived from an Anglo-Saxon word and
its symbol comes from the Latin word
‘Aurum’?
SSC CHSL 31/05/2022 (Evening)
(a) Argon (b) Gold (c) Aluminium (d) Silver
Sol.50.(b) The atomic number of gold is
79 and its symbol is Au, which is derived
from the Anglo Saxon word. The top
producers of Gold in the world are China,
Australia, Russia, and the United States.
Q.51. Which metal sulphate, composed
of potassium, aluminium, and sulphate
ions in the ratio 1 : 1 : 2, plays a role as a
?ame retardant, a mordant and an
astringent?
SSC CHSL 31/05/2022 (Evening)
(a) Gypsum (b) Potash alum
(c) Epsom salts (d) Celestite
Sol.51.(b) Potash alum (Potassium
Aluminium sulphate). The chemical
formula of potash alum is
K
2
SO
4
.Al
2
(SO
4
)
3
.24H
2
O. It is also
commonly referred to as ‘?tkari. ’
Extracted from a mineral called alunite. It
is used for the puri?cation of impure
water, stops bleeding, and is mordant for
the dyeing industry, leather tanning,
?reproof textiles, and baking powder.
Q.52. Ozone is an allotrope of ______.
SSC CGL 12/04/2022 (Morning)
(a) carbon dioxide (b) oxygen
(c) hydrogen (d) nitrogen
Sol.52.(b) Oxygen. Ozone (O
3
) is a
triatomic allotrope of oxygen. Ozone is a
powerful oxidant (far more so than
dioxygen) and has many industrial and
consumer applications related to
oxidation.
Q.53. How many protons are there in a
lithium nucleus?
SSC CGL 18/04/2022 (Evening)
(a) 2 (b) 4 (c) 5 (d) 3
Sol.53.(d) 3. Lithium has 3 protons, 3
electrons and 4 neutrons.
Q.54. Which of the following is a
low-grade brown coal that is soft with
high moisture content?
SSC MTS 11/10/2021 (Morning)
(a) Bituminous (b) Anthracite
(c) Peat (d) Lignite
Sol.54.(d) Lignite coal or brown coal, is
the lowest grade coal with the least
concentration of carbon. Lignite has a
low heating value and is mainly used in
electricity generation.
Q.55. Which of the following is a property
of silicon dioxide?
SSC MTS 11/10/2021 (Evening)
(a) It conducts electricity.
(b) It is soft.
(c) It is soluble in water.
(d) It has a high melting point.
Sol.55.(d) Silicon dioxide (SiO
2
) has a
high melting point. It has melting and
boiling points as 1713º C and 2950º C,
respectively. The density is about 2.648
g/cm
3
.
Q.56. Which of the following minerals
has kieserite as its ore ?
SSC MTS 12/10/2021 (Morning)
(a) Silver (b) Magnesium
(c) Potassium (d) Iron
Sol.56.(b) Magnesium . Kieserite is a
magnesium sulphate mineral. It is used
in the production of Epsom salt and as a
fertiliser in agriculture.
Q.57. Identify the alloy among the
following of which lead is a component.
SSC MTS 26/10/2021 (Morning)
(a) Alnico (b) Solder
(c) Nickel (d) Constantan
Sol.57.(b) Solder is a metal alloy usually
made of tin and lead. Alnico - aluminium
(Al), nickel (Ni), and cobalt (Co).
Constantan - A copper-nickel alloy used
in electrical work for its high resistance.
Q.58. Which of the following is one of the
metals used in LED semiconductor
technology?
SSC CGL 16/08/2021 (Afternoon)
(a) Iron (b) Copper (c) Gallium (d) Zinc
Sol.58.(c) Gallium is a metallic material
that is found as a trace element in coal,
bauxite, and other minerals. Other metals
such as arsenic, indium, and the
rare-earth elements (REEs) cerium,
europium, gadolinium, lanthanum,
terbium, and yttrium are also used in LED
semiconductor technology.
Q.59. Which of the following metals
reacts with the moist carbon dioxide in
the air and slowly loses its shiny brown
surface and gains a green coat?
SSC CHSL 16/04/2021 (Afternoon)
(a) Silver (b) Iron (c) Zinc (d) Copper
Sol.59.(d) Copper (Cu, Group - 11,
Atomic number - 29) . The green
substance is basic copper carbonate
(CuCO
3
).
Q.60. Which one of the following
features is NOT shown by metals?
SSC CHSL 9/8/2021 (Morning)
(a) Looks dull
(b) Can be pounded into shape
(c) Can be made into a wire
(d) Conducts heat
Sol.60.(a) Looks dull. Physical properties
of metals: high melting points, good
conductors of electricity, good
conductors of heat, high density,
malleable, ductile, lustrous.
Q.61. What is the Atomic Number of the
element Einsteinium?
SSC CPO 23/11/2020 (Morning)
(a) 99 (b) 98 (c) 101 (d) 100
Sol.61.(a) 99. Einsteinium (Es), synthetic
chemical element of the actinoid series
of the periodic table.
Q.62. Which of the following is an
example of a pair of Isobars?
SSC CHSL 17/03/2020 (Evening)
(a) Chlorine and oxygen
(b) Calcium and argon
(c) Oxygen and carbon
(d) Hydrogen and Helium
Sol.62.(b) Calcium (Ca, 20) and argon
( Ar, 18).The mass number of both these
elements is 40u.
Q.63. Which is the rarest element?
SSC CHSL 26/10/2020 (Afternoon)
(a) Astatine (b) Radon
(c) Uranium (d) Lithium
Sol.63.(a) Astatine is the rarest element
in the earth’s crust occurring only as the
decay product of various heavier
elements. All of astatine’s isotopes are
short-lived.
Q.64. Which of the following is used as a
substitute of mercury in thermometers?
SSC CGL 5/3/2020 (Evening)
(a) Selenium (b) Arsenic
(c) Bromine (d) Galinstan
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