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All questions of Classification of Elements and Periodicity in Properties for JEE Exam
The valence of sodium with atomic number 11 is:- a)4
- b)1
- c)3
- d)2
Correct answer is option 'B'. Can you explain this answer?
The valence of sodium with atomic number 11 is:
a)
4
b)
1
c)
3
d)
2
|
Rohan Singh answered |
For Sodium Na - 2,8,1 and chlorine Cl-2,8,7. Both Na and Cl require 1 electron either to loose or to gain ,so they can attain stable configuration. Therefore Na has +1 and Cl -1 valency. Valence electrons are the outermost electrons, and are the ones involved in bonding.
Lothar Meyer proposed that on arranging the elements in order of increasing atomic weights; similarities appear in which type of properties?- a)Only physical properties
- b)Only chemical properties
- c)In both physical and chemical properties
- d)thermodynamic properties
Correct answer is option 'C'. Can you explain this answer?
Lothar Meyer proposed that on arranging the elements in order of increasing atomic weights; similarities appear in which type of properties?
a)
Only physical properties
b)
Only chemical properties
c)
In both physical and chemical properties
d)
thermodynamic properties
|
Anoushka Yadav answered |
Lothar Meyer proposed the periodic table in 1864. He arranged the elements in order of increasing atomic weights. He noticed that similarities appeared in both physical and chemical properties of the elements. The correct answer is option 'C' which means similarities appear in both physical and chemical properties.
Explanation:
The periodic table arranges the elements in a way that helps in understanding their properties. The modern periodic table is based on the electronic configuration of the elements. But the original periodic table was based on the atomic weight of the elements. Lothar Meyer was the first to realize that there is a periodicity in the properties of the elements when they are arranged in order of increasing atomic weights.
Physical properties are those that can be observed or measured without changing the chemical composition of the substance. Some examples of physical properties are:
- Melting point
- Boiling point
- Density
- Electrical conductivity
- Thermal conductivity
- Atomic radius
- Ionic radius
- Electronegativity
Chemical properties are those that can be observed during a chemical reaction. Some examples of chemical properties are:
- Reactivity with acids
- Reactivity with oxygen
- Reactivity with water
- Reduction potential
- Oxidation potential
Meyer observed that when the elements are arranged in order of increasing atomic weights, there is a periodicity in their physical and chemical properties. This means that elements with similar atomic weights have similar physical and chemical properties. For example, lithium, sodium, and potassium have similar physical and chemical properties because they all belong to the same group and have similar atomic weights.
Conclusion:
Lothar Meyer proposed the periodic table in 1864. He arranged the elements in order of increasing atomic weights. He noticed that similarities appeared in both physical and chemical properties of the elements. When the elements are arranged in order of increasing atomic weights, there is a periodicity in their physical and chemical properties.
Explanation:
The periodic table arranges the elements in a way that helps in understanding their properties. The modern periodic table is based on the electronic configuration of the elements. But the original periodic table was based on the atomic weight of the elements. Lothar Meyer was the first to realize that there is a periodicity in the properties of the elements when they are arranged in order of increasing atomic weights.
Physical properties are those that can be observed or measured without changing the chemical composition of the substance. Some examples of physical properties are:
- Melting point
- Boiling point
- Density
- Electrical conductivity
- Thermal conductivity
- Atomic radius
- Ionic radius
- Electronegativity
Chemical properties are those that can be observed during a chemical reaction. Some examples of chemical properties are:
- Reactivity with acids
- Reactivity with oxygen
- Reactivity with water
- Reduction potential
- Oxidation potential
Meyer observed that when the elements are arranged in order of increasing atomic weights, there is a periodicity in their physical and chemical properties. This means that elements with similar atomic weights have similar physical and chemical properties. For example, lithium, sodium, and potassium have similar physical and chemical properties because they all belong to the same group and have similar atomic weights.
Conclusion:
Lothar Meyer proposed the periodic table in 1864. He arranged the elements in order of increasing atomic weights. He noticed that similarities appeared in both physical and chemical properties of the elements. When the elements are arranged in order of increasing atomic weights, there is a periodicity in their physical and chemical properties.
In Na2O oxidation state of oxygen is:- a)+2
- b)-1
- c)0
- d)+1
Correct answer is option 'D'. Can you explain this answer?
In Na2O oxidation state of oxygen is:
a)
+2
b)
-1
c)
0
d)
+1
|
Geetika Shah answered |
In Na2O oxidation state of Na is +1.
It gains 2 electrons so, the oxidation state is +1 which is equal to one oxygen atom (2 electrons)
It gains 2 electrons so, the oxidation state is +1 which is equal to one oxygen atom (2 electrons)
Horizontal rows in the periodic table are called:- a)Cell
- b)Table
- c)Groups
- d)Periods
Correct answer is option 'D'. Can you explain this answer?
Horizontal rows in the periodic table are called:
a)
Cell
b)
Table
c)
Groups
d)
Periods
|
|
Rohan Singh answered |
The Periodic Table: Families and Periods. In the periodic table of elements, there are seven horizontal rows of elements called periods. The vertical columns of elements are called groups, or families.
Sodium forms which types of oxides?- a)Acidic
- b)Basic
- c)Neutral
- d)Amphoteric
Correct answer is option 'B'. Can you explain this answer?
Sodium forms which types of oxides?
a)
Acidic
b)
Basic
c)
Neutral
d)
Amphoteric
|
Pooja Mehta answered |
Basic oxides are always oxides of metals. They combine with water to form bases which are usually called metal hydroxides. Na2O, MgO, CaO, FeO and CuO are examples of basic oxides. Acidic oxides are mostly oxides of non-metals, and they dissolve in water to form acids.
Can you explain the answer of this question below:In the modern periodic table, which period contains 32 elements?
- A:
Sixth
- B:
First
- C:
Seventh
- D:
Second
The answer is a.
In the modern periodic table, which period contains 32 elements?
Sixth
First
Seventh
Second
|
Preeti Iyer answered |
The answer is c.
The total number of electrons that can be accommodated in seventh period are 2 ( in 7s) + 14(in 5f) + 10(in 6d )+ 6(in 7p) = 32. The maximum number of elements present in it is 32.
Among the following statements the one that is not true about Mendeleev’s Periodic Table is:- a)Elements of group 7 and 8 were arranged on the basis of equivalent weights
- b)Some elements in the same group differ in their properties
- c)Elements were arranged on the basis of atomic weights
- d)The position of hydrogen was not justified
Correct answer is option 'A'. Can you explain this answer?
Among the following statements the one that is not true about Mendeleev’s Periodic Table is:
a)
Elements of group 7 and 8 were arranged on the basis of equivalent weights
b)
Some elements in the same group differ in their properties
c)
Elements were arranged on the basis of atomic weights
d)
The position of hydrogen was not justified
|
Om Desai answered |
In Mendeleev’s periodic table, elements were arranged on the basis of atomic weights.
Which block of the periodic table contains the man made elements?- a)p block
- b)s block
- c)f block
- d)d block
Correct answer is option 'C'. Can you explain this answer?
Which block of the periodic table contains the man made elements?
a)
p block
b)
s block
c)
f block
d)
d block
|
|
Raghav Bansal answered |
Most of the f block elements, lanthanoids and actinoids are man made/synthetic/prepared in the lab. Especially actinoids.
Eka silicon predicted by Mendeleev is which element:- a)Germanium
- b)Aluminium
- c)Gallium
- d)Sodium
Correct answer is option 'A'. Can you explain this answer?
Eka silicon predicted by Mendeleev is which element:
a)
Germanium
b)
Aluminium
c)
Gallium
d)
Sodium
|
Suresh Iyer answered |
Mendeleev predicted the existence of 'eka-silicon', which would fit into a gap next to silicon. The element germanium was discovered later. Its properties were found to be similar to the predicted ones and confirmed Mendeleev's periodic table.
The lanthanide series starts with:
- a)Thorium
- b)Lutetium
- c)Lawrencium
- d)cerium
Correct answer is option 'D'. Can you explain this answer?
The lanthanide series starts with:
a)
Thorium
b)
Lutetium
c)
Lawrencium
d)
cerium
|
|
Suresh Reddy answered |
The lanthanide series starts from cerium and ends in lutetium
Which of the following is the most non-metallic element?- a)F
- b)Si
- c)N
- d)B
Correct answer is option 'A'. Can you explain this answer?
Which of the following is the most non-metallic element?
a)
F
b)
Si
c)
N
d)
B
|
Nandini Patel answered |
The non-metallic character increases as we go from left to right across the periodic table. Hence, fluorine (F) is most non-metallic. Further F has maximum tendency to accept an electron characteristic of non-metal.
Which of the following pairs have both the members from the same group of periodic table?- a)Mg, Cl
- b)Mg, Cu
- c)Mg, Be
- d)Mg, Na
Correct answer is option 'C'. Can you explain this answer?
Which of the following pairs have both the members from the same group of periodic table?
a)
Mg, Cl
b)
Mg, Cu
c)
Mg, Be
d)
Mg, Na
|
Neha Joshi answered |
The elements in the group include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
What is the relationship between the number of elements in each period and the number of atomic orbitals available in the energy level that is being filled?- a)Number of elements is twice the number of atomic orbitals.
- b)Number of elements is three times the number of atomic orbitals.
- c)Number of elements is half the number of atomic orbitals.
- d)Number of elements is same as the number of atomic orbitals.
Correct answer is 'A'. Can you explain this answer?
What is the relationship between the number of elements in each period and the number of atomic orbitals available in the energy level that is being filled?
a)
Number of elements is twice the number of atomic orbitals.
b)
Number of elements is three times the number of atomic orbitals.
c)
Number of elements is half the number of atomic orbitals.
d)
Number of elements is same as the number of atomic orbitals.
|
Krishna Iyer answered |
The number of elements in each period is twice the number of atomic orbitals available in the energy level that is being filled.
Let's understand it by taking the elements of the 4th period.
In the fourth period, there are 18 elements. The types of subshells used in the 4th period are s, p, and d.
Number of orbitals of s subshell = 1
Number of orbitals of p subshell = 3
Number of orbitals of d subshell = 5
Total number of orbitals = 9
The total number of elements is 18 i.e. twice the total number of orbitals.
In the fourth period, there are 18 elements. The types of subshells used in the 4th period are s, p, and d.
Number of orbitals of s subshell = 1
Number of orbitals of p subshell = 3
Number of orbitals of d subshell = 5
Total number of orbitals = 9
The total number of elements is 18 i.e. twice the total number of orbitals.
Which scientist proposed that atomic number is more fundamental property of an element than its atomic mass?- a)Newlands
- b)Lothar Meyer
- c)Henry Moseley
- d)Meyer
Correct answer is option 'C'. Can you explain this answer?
Which scientist proposed that atomic number is more fundamental property of an element than its atomic mass?
a)
Newlands
b)
Lothar Meyer
c)
Henry Moseley
d)
Meyer
|
|
Pooja Shah answered |
The scientist who first of all showed that the atomic number is more fundamental property of an element than its atomic mass was Henry Moseley.
Johann Dobereiner classified elements in group of three elements called as- a)Trinity
- b)Trials
- c)Triads
- d)Diads
Correct answer is option 'C'. Can you explain this answer?
Johann Dobereiner classified elements in group of three elements called as
a)
Trinity
b)
Trials
c)
Triads
d)
Diads
|
|
Om Desai answered |
In 1829, Johann Dobereiner, a German scientist made some groups of three elements each and called them triads.
He observed that the atomic mass of the middle element of a triad was nearly equal to the arithmetic mean of the atomic masses of the other two elements. All three elements of a triad were similar in their properties.
According to Dobereiner’s law of triads the number of elements present in each group is:
- a)2
- b)4
- c)5
- d)3
Correct answer is option 'D'. Can you explain this answer?
According to Dobereiner’s law of triads the number of elements present in each group is:
a)
2
b)
4
c)
5
d)
3
|
|
Geetika Shah answered |
- According to Dobereiner's law of triads each triad contains three elements.
- He also noticed that the middle element of each of the triads had an atomic weight about halfway between the atomic weights of the other two.
Eka aluminium predicted by Mendeleev is which element?- a)Germanium
- b)Magnesium
- c)Gallium
- d)Sodium
Correct answer is option 'C'. Can you explain this answer?
Eka aluminium predicted by Mendeleev is which element?
a)
Germanium
b)
Magnesium
c)
Gallium
d)
Sodium
|
|
Gaurav Kumar answered |
Eka aluminium predicted by Mendeleev is Gallium. Eka-aluminium and gallium are the two names of the same element as Eka -Aluminum has almost exactly the same properties as the actual properties of the gallium element.
Which of the following is an ionic hydride?- a)PH3
- b)H2S
- c)HI
- d)KH
Correct answer is option 'D'. Can you explain this answer?
Which of the following is an ionic hydride?
a)
PH3
b)
H2S
c)
HI
d)
KH
|
Mohit Rajpoot answered |
Ionic hydrides are commonly known as saline hydrides or pseudohalides. These compounds form between hydrogen and the most active metals, especially with the alkali and alkaline-earth metals of group one and two elements.
In this group, the hydrogen acts as the hydride ion (H−). They bond with more electropositive metal atoms. Ionic hydrides are usually binary compounds (i.e., only two elements in the compound) and are also insoluble in solutions. Now I hope you can form your own examples, but common examples are Sodium Hydride (NaH), Lithium hydride (LiH), Potassium hydride (KH) etc.
Moseley performed experiments and studied the frequencies of which radiations emitted from the elements?- a)Gamma rays
- b)X-rays
- c)UV rays
- d)Infra red rays
Correct answer is option 'B'. Can you explain this answer?
Moseley performed experiments and studied the frequencies of which radiations emitted from the elements?
a)
Gamma rays
b)
X-rays
c)
UV rays
d)
Infra red rays
|
|
Naina Bansal answered |
Moseley performed experiments and studied the frequencies of the X-rays emitted from the elements.
Elements in the same group have same:- a)Number of valence electrons
- b)Density
- c)Atomic radius
- d)Nuclear charge
Correct answer is option 'A'. Can you explain this answer?
Elements in the same group have same:
a)
Number of valence electrons
b)
Density
c)
Atomic radius
d)
Nuclear charge
|
Lavanya Menon answered |
- Elements in the same group have the same number of valence electrons in their outermost shell, hence, have similar properties.
- Elements in the same period don't have same number of valence electrons, hence, have different properties. But, elements in the same period have same number of shells.
The first period has how many orbitals?- a)1
- b)3
- c)2
- d)4
Correct answer is option 'A'. Can you explain this answer?
The first period has how many orbitals?
a)
1
b)
3
c)
2
d)
4
|
|
Raghav Bansal answered |
1st period contains only 2 elements hydrogen and helium having atomic no. 1 and 2 respectively.
The electronic configuration of hydrogen is 1s1 while that of helium is 1s2. Both contain only s subshell. S subshell that only contains 1 orbital i.e. z.
Thus, 1st period has 1 orbital.
The symbol for element with atomic number 111 and name Unununnium is- a)Uun
- b)Uuu
- c)UUU
- d)None of the above
Correct answer is option 'B'. Can you explain this answer?
The symbol for element with atomic number 111 and name Unununnium is
a)
Uun
b)
Uuu
c)
UUU
d)
None of the above
|
|
Gaurav Kumar answered |
- The element was to be called unununium (with the corresponding symbol of Uuu),a systematic element name as a placeholder, until the element was discovered (and the discovery then confirmed) and a permanent name was decided on.
- Although widely used in the chemical community on all levels, from chemistry classrooms to advanced textbooks, the recommendations were mostly ignored among scientists in the field, who called it element 111, with the symbol of E111, (111) or even simply 111.
The oxygen family is also known as:- a)halogen family
- b)oxo family
- c)chalcogen family
- d)peroxo family
Correct answer is option 'C'. Can you explain this answer?
The oxygen family is also known as:
a)
halogen family
b)
oxo family
c)
chalcogen family
d)
peroxo family
|
|
Rajat Kapoor answered |
The Oxygen family, sometimes also known as chalcogens, is group 16 on the periodic table and consisted of oxygen, sulfur, selenium, tellurium, polonium and ununhexium.
The basis of long form of periodic table is:- a)Mass number
- b)Atomic weight
- c)Atomic number
- d)Ionic radius
Correct answer is option 'C'. Can you explain this answer?
The basis of long form of periodic table is:
a)
Mass number
b)
Atomic weight
c)
Atomic number
d)
Ionic radius
|
|
Nandini Patel answered |
In long form of periodic table elements are arranged in increasing order of their Atomic number.
The nature of bonds in the compounds of carbon is mostly:- a)Electrovalent
- b)Covalent as well as electrovalent
- c)Covalent
- d)Metallic
Correct answer is option 'C'. Can you explain this answer?
The nature of bonds in the compounds of carbon is mostly:
a)
Electrovalent
b)
Covalent as well as electrovalent
c)
Covalent
d)
Metallic
|
|
Rajat Kapoor answered |
The atomic no. of carbon is 6 which means that a nutral atom of carbon contains 6 electrons .so, the electronic confugration of carbon is 2 and 4. Since a corbon atom has 4 electrons in tis outermost cell ,so it should either lose 4 electrons or gain 4 electrons to achieve the inert gas electron configuration and become stable,its not possible to remove 4 electrons from a carbon atom,its not possible to add as many as 4 electrons to a carbon atom,,therefore carbon atoms can achieve the inert gas electron arrangment only by the sharing of electrons,tthere fore ,carbon alwayz forms covalent bonds.
Mendeleev predicted the existence of which element/elements in the periodic table?- a)Gallium
- b)Sodium and germanium
- c)Gallium and germanium
- d)Germanium and Gold
Correct answer is option 'C'. Can you explain this answer?
Mendeleev predicted the existence of which element/elements in the periodic table?
a)
Gallium
b)
Sodium and germanium
c)
Gallium and germanium
d)
Germanium and Gold
|
|
Neha Joshi answered |
Gallium and Germanium were the elements not discovered at that time and Mendeleev put gaps in the periodic table.
Gallium was called as Eka aluminium
Germanium was called as Eka silicon
Gallium was called as Eka aluminium
Germanium was called as Eka silicon
How many orbitals are filled in second period?- a)6
- b)3
- c)1
- d)4
Correct answer is option 'D'. Can you explain this answer?
How many orbitals are filled in second period?
a)
6
b)
3
c)
1
d)
4
|
|
Lavanya Menon answered |
The 4 orbitals filled in second period are one 2s (with 2 electrons) and three 2p (with 6 electrons).
Choose the correct statement:- a)Across a period electropositivity of elements increases
- b)Across a period basic nature of oxides increases
- c)Across a period acidic nature of oxides increases
- d)Across a period metallic character increases
Correct answer is option 'C'. Can you explain this answer?
Choose the correct statement:
a)
Across a period electropositivity of elements increases
b)
Across a period basic nature of oxides increases
c)
Across a period acidic nature of oxides increases
d)
Across a period metallic character increases
|
|
Geetika Shah answered |
The non metallic character decreases down the group.And we know the oxides of non-metal r acidic in genral.Hence acidic character of oxides decreases down d group. Down the group the size of the element increases, electronegativity decreases ,metallic character increases and hence the acidic character decrease.
Which of the following elements are called representative elements?- a)p block elements only
- b)s and p block elements only
- c)d block elements only
- d)s block elements only
Correct answer is option 'B'. Can you explain this answer?
Which of the following elements are called representative elements?
a)
p block elements only
b)
s and p block elements only
c)
d block elements only
d)
s block elements only
|
|
Gaurav Kumar answered |
The elements of "s" and "p" blocks except "d" group elements are called as representative elements. Their outer shells are not completely filled with electrons. The elements get the nearest inert gas configuration by losing or gaining or sharing of electrons.
Among the following oxides, neutral oxide is:- a)ZnO2
- b)SiO2
- c)CO
- d)SnO2
Correct answer is option 'C'. Can you explain this answer?
Among the following oxides, neutral oxide is:
a)
ZnO2
b)
SiO2
c)
CO
d)
SnO2
|
|
Shreya Gupta answered |
Neutral oxide. Neutral oxides are oxides which are neither acidic nor basic. In other words, oxides which neither react with acids or with bases are called neutral oxides. Some examples of neutral oxides are nitrous oxide (N2O), and carbon monoxide (CO).
Inert gases belong to which block of the periodic table?- a)s-block
- b)d-block
- c)p-block
- d)f-block
Correct answer is 'A'. Can you explain this answer?
Inert gases belong to which block of the periodic table?
a)
s-block
b)
d-block
c)
p-block
d)
f-block
|
|
Rajeev Saxena answered |
The six noble gases are helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Their atomic numbers are, respectively, 2, 10, 18, 36, 54, and 86.
Newland arranged elements in increasing order of atomic weights and noted that every eighth element had properties similar to:- a)Third element
- b)Fourth element
- c)Second element
- d)First element
Correct answer is option 'D'. Can you explain this answer?
Newland arranged elements in increasing order of atomic weights and noted that every eighth element had properties similar to:
a)
Third element
b)
Fourth element
c)
Second element
d)
First element
|
Hansa Sharma answered |
According to Newlands' law of octaves when the elements are arranged in order of increasing atomic weights then every eighth element has properties similar to that of the first element.
The transition elements have characteristic electronic configuration which can be represented as:- a)(n-1) d1-10 ns0-2
- b)(n-2) d1-10 (n-1) p6 ns2
- c)(n-1)s2 p6 d 10 ns2 np6 nd1-10
- d)(n-2) d1-10 (n-1) s2 p6 d1 or 2 ns1
Correct answer is option 'A'. Can you explain this answer?
The transition elements have characteristic electronic configuration which can be represented as:
a)
(n-1) d1-10 ns0-2
b)
(n-2) d1-10 (n-1) p6 ns2
c)
(n-1)s2 p6 d 10 ns2 np6 nd1-10
d)
(n-2) d1-10 (n-1) s2 p6 d1 or 2 ns1
|
|
Om Desai answered |
Transition elements are d-block elements and the characteristic electronic configuration of d block element is in option A
What is the maximum number of electrons that can be filled in 3d subshell?- a)2
- b)14
- c)6
- d)10
Correct answer is option 'D'. Can you explain this answer?
What is the maximum number of electrons that can be filled in 3d subshell?
a)
2
b)
14
c)
6
d)
10
|
|
Shreya Gupta answered |
There are 5 orbitals in d subshell and each orbital can accommodate 2 electrons. Hence maximum number of electrons that can be filled in 3d subshell is 10.
What is the principal quantum number for second period?a)1b)3c)2d)4Correct answer is option 'C'. Can you explain this answer?
|
|
Krishna Iyer answered |
Principle quantum no is defined as the no of shells an element possesses. Since every element in the 2nd period has 2 shells, therefore, principle quantum no for 2nd period is 2.
The element which shows only negative oxidation state/s among following elements is:- a)Iodine
- b)Fluorine
- c)Bromine
- d)Chlorine
Correct answer is option 'B'. Can you explain this answer?
The element which shows only negative oxidation state/s among following elements is:
a)
Iodine
b)
Fluorine
c)
Bromine
d)
Chlorine
|
|
Geetika Shah answered |
Fluorine has highest electronegativity among all known elements, so it shows only negative oxidation states.
Which of the following elements belongs to the same group as the element having configuration 1s2 2s2 2p1- a)E: (1s2 2s2 2p6 3s2 3p6 4s2)
- b)(1s2 2s2 2p6 3s2 3p3)
- c)(1s2 2s2 2p6 3s2 3p1)
- d)(1s2 2s2 2p6 3s2 3p5)
Correct answer is option 'C'. Can you explain this answer?
Which of the following elements belongs to the same group as the element having configuration 1s2 2s2 2p1
a)
E: (1s2 2s2 2p6 3s2 3p6 4s2)
b)
(1s2 2s2 2p6 3s2 3p3)
c)
(1s2 2s2 2p6 3s2 3p1)
d)
(1s2 2s2 2p6 3s2 3p5)
|
|
User2408930 answered |
C is the answer because in outer most shell of 1s^2 2s^2 2p^1
is 1 electron and also in 1s^22s2 2p6 3s2 3p1 has 1 electron in their outer most shell. so they are belonging through same group
is 1 electron and also in 1s^22s2 2p6 3s2 3p1 has 1 electron in their outer most shell. so they are belonging through same group
The maximum number of elements present in seventh period of the modern periodic table is:- a)32
- b)8
- c)2
- d)18
Correct answer is option 'A'. Can you explain this answer?
The maximum number of elements present in seventh period of the modern periodic table is:
a)
32
b)
8
c)
2
d)
18
|
Anjali Iyer answered |
The total number of electrons that can be accommodated in seventh period are 2 ( in 7s) + 14(in 5f) + 10(in 6d )+ 6(in 7p) = 32. The maximum number of elements present in it is 32.
Elements of Group-1 are called:- a)Chalcogens
- b)Alkaline earth metals
- c)Alkali metals
- d)Halogens
Correct answer is 'C'. Can you explain this answer?
Elements of Group-1 are called:
a)
Chalcogens
b)
Alkaline earth metals
c)
Alkali metals
d)
Halogens
|
|
Neha Joshi answered |
Elements of group 1, i.e. Li, Na, K, Rb, Cs and Fr, are called alkali metals because they react with water to form alkaline solutions. The pH of solutions usually range between 8-12.
Which pair of elements from different groups resembles each other the most in their chemical properties?- a)Al and Si
- b)Be and B
- c)Be and C
- d)Al and Be
Correct answer is option 'D'. Can you explain this answer?
Which pair of elements from different groups resembles each other the most in their chemical properties?
a)
Al and Si
b)
Be and B
c)
Be and C
d)
Al and Be
|
|
Rohan Singh answered |
Be and Al show diagonal relationship and hence resembles each other closely.
Elements of which group are called Halogens?- a)Group 16
- b)Group 17
- c)Group 18
- d)Group 15
Correct answer is option 'B'. Can you explain this answer?
Elements of which group are called Halogens?
a)
Group 16
b)
Group 17
c)
Group 18
d)
Group 15
|
|
Geetika Shah answered |
Group 17 elements are called halogens because halogen is a Greek word which means 'salt producing'. Halogens include fluorine, chlorine, bromine, iodine andastatine. They all are non-metals. They react with metals to form compounds called salts.
Which one of the following configuration represents a metallic character?- a)2, 8, 2
- b)2, 8, 4
- c)2, 8, 7
- d)2, 8, 8
Correct answer is option 'A'. Can you explain this answer?
Which one of the following configuration represents a metallic character?
a)
2, 8, 2
b)
2, 8, 4
c)
2, 8, 7
d)
2, 8, 8
|
|
Pooja Shah answered |
Option ‘a’ represents metallic character of Mg. All others remaining represent nonmetals and metalloids.
The metallic character of group 14 elements:- a)Decreases and then increases.
- b)Increases from top to bottom in group.
- c)Remains same for all elements of group.
- d)Decreases from top to bottom in group.
Correct answer is option 'B'. Can you explain this answer?
The metallic character of group 14 elements:
a)
Decreases and then increases.
b)
Increases from top to bottom in group.
c)
Remains same for all elements of group.
d)
Decreases from top to bottom in group.
|
|
Preeti Iyer answered |
The metallic character of group 14 elements increases from top to bottom because removal of electron becomes easier on moving down the group. Metallic character increases as you move down an element group in the periodic table. This is because electrons become easier to lose as the atomic radius increases, where there is less attraction between the nucleus and the valence electrons because of the increased distance between them.
Oxygen exhibits +2 oxidation state in the compound:- a)MgO
- b)Na2O
- c)OF2
- d)H2O
Correct answer is option 'C'. Can you explain this answer?
Oxygen exhibits +2 oxidation state in the compound:
a)
MgO
b)
Na2O
c)
OF2
d)
H2O
|
|
Shreya Gupta answered |
Oxygen almost always has an oxidation number of -2, except in H2O2 (when it is -1) and in OF2 (when it is +2). Hydrogen always has an oxidation number of +1 in compounds which contain elements that are more electronegative than it is.
Which of these compounds is a basic oxide?- a)MgO
- b)Cl2O7
- c)CO2
- d)SO2
Correct answer is option 'A'. Can you explain this answer?
Which of these compounds is a basic oxide?
a)
MgO
b)
Cl2O7
c)
CO2
d)
SO2
|
Shreya Sriram answered |
A basic oxide is one which dissolves in water gives a base. MgO when dissolved in water gives Mg(OH)2 which is a base and others give acids
Which element acts as strong reducing agent?- a)Those elements that can share electron
- b)The elements which readily lose electron
- c)The elements which readily gain electron
- d)None of above
Correct answer is option 'B'. Can you explain this answer?
Which element acts as strong reducing agent?
a)
Those elements that can share electron
b)
The elements which readily lose electron
c)
The elements which readily gain electron
d)
None of above
|
|
Krishna Iyer answered |
Reducing agents reduce others by oxidizing itself. Elements which lose electron become oxidize and reduce other elements by donating electron.
The 3d transition series starts from which atomic number?- a)19
- b)21
- c)20
- d)22
Correct answer is option 'B'. Can you explain this answer?
The 3d transition series starts from which atomic number?
a)
19
b)
21
c)
20
d)
22
|
Ishani Pillai answered |
The 3d transition series starts from atomic number 21, which is the element Scandium (Sc).
Explanation:
- The transition elements or transition metals are a group of elements in the periodic table that have partially filled d orbitals in their valence shells.
- The 3d transition series refers to the elements that have their d orbitals filled progressively, from scandium (Sc) to zinc (Zn), as the atomic number increases.
- Scandium has an atomic number of 21, which means it has 21 protons in its nucleus and 21 electrons surrounding it.
- Scandium is the first element in the 3d transition series and has one electron in its 3d orbital.
- The other elements in the 3d transition series are titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn).
- These elements have their d orbitals filled progressively, from 1 electron in Sc to 10 electrons in Zn.
- The 4d and 5d transition series follow the same pattern, with the d orbitals being progressively filled from the first element in each series.
Therefore, the correct answer is option B, 21.
Explanation:
- The transition elements or transition metals are a group of elements in the periodic table that have partially filled d orbitals in their valence shells.
- The 3d transition series refers to the elements that have their d orbitals filled progressively, from scandium (Sc) to zinc (Zn), as the atomic number increases.
- Scandium has an atomic number of 21, which means it has 21 protons in its nucleus and 21 electrons surrounding it.
- Scandium is the first element in the 3d transition series and has one electron in its 3d orbital.
- The other elements in the 3d transition series are titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), and zinc (Zn).
- These elements have their d orbitals filled progressively, from 1 electron in Sc to 10 electrons in Zn.
- The 4d and 5d transition series follow the same pattern, with the d orbitals being progressively filled from the first element in each series.
Therefore, the correct answer is option B, 21.
On moving down a group the number of valence electrons:- a)Remains the same
- b)Increases
- c)Decreases and then increases
- d)Decreases
Correct answer is option 'A'. Can you explain this answer?
On moving down a group the number of valence electrons:
a)
Remains the same
b)
Increases
c)
Decreases and then increases
d)
Decreases
|
|
Geetika Shah answered |
On moving down a group since the number of valence electrons remains the same, all elements exhibit same valence.
Chapter doubts & questions for Classification of Elements and Periodicity in Properties - Chemistry for JEE Main & Advanced 2025 is part of JEE exam preparation. The chapters have been prepared according to the JEE exam syllabus. The Chapter doubts & questions, notes, tests & MCQs are made for JEE 2025 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests here.
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