Page 1
ATOMIC STRUCTURE (SET -B) TEST-1
(Medical)
1. Which of the following set of quantum numbers
belong to highest energy
(a) n = 4, ? = 0, m = 0, s = +
2
1
(b) n = 3, ? = 0, m = 0, s = +
2
1
(c) n = 3, ? = 1, m = 1, s = +
2
1
(d) n = 3, ? = 2, m = 1, s = +
2
1
2. Which is not true with respect to cathode rays
(a) A stream of electrons
(b) Charged particles
(c) Move with speed same as that of light
(d) Can be deflected by magnetic fields
3. An element has atomic number 11 and mass
number 24. What does the nucleus contain
(a) 11 protons, 13 neutrons
(b) 11 protons, 13 neutrons, 13 electrons
(c) 13 protons, 11 neutrons
(d) 13 protons, 11 electrons
4. The hydride ion is isoelectronic with
(a) H
+
(b) He
+
(c) He (d) Be
5. Planck’s constant has the same dimensions as
that of
(a) Power
(b) Work
(c) Radiant energy
(d) Angular momentum
6. The orbital momentum for an electron revolving
in an orbit is given by
p
+
2
h
. ) 1 ( ? ? . This
momentum for an s-electron will be given by
(a) +
p 2
h
.
2
1
(b) zero
(c)
p 2
h
(d) 2
p 2
h
7. Which orbital of carbon can absorb photon but
not emit it
(a) 1 s (b) 2 s
(c) 3 p (d) 2 p
8. Brackett series are produced when the electrons
from the outer orbits jump to
(a) 2
nd
orbit (b) 3
rd
orbit
(c) 4
th
orbit (d) 5
th
orbit
9. The spectrum of He is expected to be similar to
that of
(a) H (b) Na
(c) He
+
(d) Li
+
10. In Bohr series of lines of hydrogen spectrum the
third line from the red end corresponds to
which one of the following inter–orbit jumps of
the electron for Bohr orbits is an atom of
hydrogen
(a) 3 ? 2 (b) 5 ? 2
(c) 4 ? 1 (d) 2 ? 5
11. In hydrogen atom, energy of first excited state is
–3. 4 eV. Then find out the KE of the same orbit
of hydrogen
(a) + 3.4 eV (b) + 6.8 eV
(c) – 13.6 eV (d) + 13.6 eV
12. The energy of an electron in nth orbit of
hydrogen atoms is
(a) eV
n
6 . 13
4
(b) eV
n
6 . 13
3
(c) eV
n
6 . 13
2
(d) eV
n
6 . 13
13. The value of the energy for the first excited state
of hydrogen atom will be
(a) –13.6 eV (b) –3.40 eV
(c) –1.51 eV (d) –0.85 eV
Page 2
ATOMIC STRUCTURE (SET -B) TEST-1
(Medical)
1. Which of the following set of quantum numbers
belong to highest energy
(a) n = 4, ? = 0, m = 0, s = +
2
1
(b) n = 3, ? = 0, m = 0, s = +
2
1
(c) n = 3, ? = 1, m = 1, s = +
2
1
(d) n = 3, ? = 2, m = 1, s = +
2
1
2. Which is not true with respect to cathode rays
(a) A stream of electrons
(b) Charged particles
(c) Move with speed same as that of light
(d) Can be deflected by magnetic fields
3. An element has atomic number 11 and mass
number 24. What does the nucleus contain
(a) 11 protons, 13 neutrons
(b) 11 protons, 13 neutrons, 13 electrons
(c) 13 protons, 11 neutrons
(d) 13 protons, 11 electrons
4. The hydride ion is isoelectronic with
(a) H
+
(b) He
+
(c) He (d) Be
5. Planck’s constant has the same dimensions as
that of
(a) Power
(b) Work
(c) Radiant energy
(d) Angular momentum
6. The orbital momentum for an electron revolving
in an orbit is given by
p
+
2
h
. ) 1 ( ? ? . This
momentum for an s-electron will be given by
(a) +
p 2
h
.
2
1
(b) zero
(c)
p 2
h
(d) 2
p 2
h
7. Which orbital of carbon can absorb photon but
not emit it
(a) 1 s (b) 2 s
(c) 3 p (d) 2 p
8. Brackett series are produced when the electrons
from the outer orbits jump to
(a) 2
nd
orbit (b) 3
rd
orbit
(c) 4
th
orbit (d) 5
th
orbit
9. The spectrum of He is expected to be similar to
that of
(a) H (b) Na
(c) He
+
(d) Li
+
10. In Bohr series of lines of hydrogen spectrum the
third line from the red end corresponds to
which one of the following inter–orbit jumps of
the electron for Bohr orbits is an atom of
hydrogen
(a) 3 ? 2 (b) 5 ? 2
(c) 4 ? 1 (d) 2 ? 5
11. In hydrogen atom, energy of first excited state is
–3. 4 eV. Then find out the KE of the same orbit
of hydrogen
(a) + 3.4 eV (b) + 6.8 eV
(c) – 13.6 eV (d) + 13.6 eV
12. The energy of an electron in nth orbit of
hydrogen atoms is
(a) eV
n
6 . 13
4
(b) eV
n
6 . 13
3
(c) eV
n
6 . 13
2
(d) eV
n
6 . 13
13. The value of the energy for the first excited state
of hydrogen atom will be
(a) –13.6 eV (b) –3.40 eV
(c) –1.51 eV (d) –0.85 eV
14. The wavelength associated with a golf ball
weighing 200 g and moving at a speed of 5 m/h
is of the order
(a) 10
–10
m (b) 10
–20
m
(c) 10
–30
m (d) 10
–40
m
15. Number of neutrons in nitride ion (N
-3
)
(a) 4 (b) 5
(c) 6 (d) 7
16. The uncertainty in the position of an electron
(mass = 9.1 x 10
–28
g) moving with a velocity of
3.0 x 10
4
cm s
–1
accurate upto 0.011% will be
(a) 1.92 cm (b) 7.68 cm
(c) 0.175 cm (d) 3.84 cm
17. The uncertainty in the momentum of an electron
is 1.0 x 10
–5
kg ms
–1
. The uncertainty in its
position will be (h = 6.62 x 10
–34
kg m
2
s
–1
)
(a) 1.05 x 10
–26
m (b) 1.05 x 10
–28
m
(c) 5.27 x 10
–30
m (d) 5.25 x 10
–28
m
18. Which of the following is possible
n ? m
l
m
s
(a) 3 2 1 0
(b) 3 0 0 –
2
1
(c) 1 2 2
2
1
(d) 1 0 1
2
1
19. The total number of orbitals in a shell with
principal quantum number ‘n’ is
(a) 2n (b) 2n
2
(c) n
2
(d) n
20. Which one of the following set of quantum
numbers is not possible for 4 p electron
(a) n = 4, ? = 1, m = –1, m
S
= +
2
1
(b) n = 4, ? = 1, m = 0, m
S
= +
2
1
(c) n = 4, ? = 1, m = 2, m
S
= +
2
1
(d) n = 4, ? = 1, m = –1, m
S
= –
2
1
21. For a f–orbital, the values of m are
(a) –2, –1, 0, +1, + 2
(b) –3, –2, –1, 0, +1, +2, 3
(c) –1, 0, +1
(d) 0, +1, +2, +3
22. The number of d–electrons retained in Fe
2+
(At.
no. of Fe = 26) ion is
(a) 3 (b) 4
(c) 5 (d) 6
23. If the nitrogen atom had electronic configuration
1s
7
it would have energy lower than that of the
normal ground state configuration 1s
2
2s
2
2p
3
because the electrons would be closer to the
nucleus. Yet 1s
7
is not observed. It violates
(a) Heisenberg’s uncertainty principle
(b) Hund’s rule
(c) Pauli exclusion principle
(d) Bohr postulate of stationary orbits
24. Which of the following ions has the maximum
magnetic moment
(a) Mn
2+
(b) Fe
2+
(c) Ti
2+
(d) Cr
2+
25. Which principle / rule limits the maximum no.
of electrons in an orbital to two
(a) Aufbau principle
(b) Pauli’s exclusion principle
(c) Hund’s rule of max. multiplicity
(d) Heisenberg’s uncertainty principle
Assertion –Reason
In every question a statement of ASSERTION
is followed by a statement of REASON .Mark
the correct answer out of the following choices:
(a) If both ASSERTION and REASON are
true and reason is the correct explanation of
the assertion.
(b) If both ASSERTION and REASON are
true but reason is not the correct explanation of
the assertion
(c) If ASSERTION is true but REASON is
false
Page 3
ATOMIC STRUCTURE (SET -B) TEST-1
(Medical)
1. Which of the following set of quantum numbers
belong to highest energy
(a) n = 4, ? = 0, m = 0, s = +
2
1
(b) n = 3, ? = 0, m = 0, s = +
2
1
(c) n = 3, ? = 1, m = 1, s = +
2
1
(d) n = 3, ? = 2, m = 1, s = +
2
1
2. Which is not true with respect to cathode rays
(a) A stream of electrons
(b) Charged particles
(c) Move with speed same as that of light
(d) Can be deflected by magnetic fields
3. An element has atomic number 11 and mass
number 24. What does the nucleus contain
(a) 11 protons, 13 neutrons
(b) 11 protons, 13 neutrons, 13 electrons
(c) 13 protons, 11 neutrons
(d) 13 protons, 11 electrons
4. The hydride ion is isoelectronic with
(a) H
+
(b) He
+
(c) He (d) Be
5. Planck’s constant has the same dimensions as
that of
(a) Power
(b) Work
(c) Radiant energy
(d) Angular momentum
6. The orbital momentum for an electron revolving
in an orbit is given by
p
+
2
h
. ) 1 ( ? ? . This
momentum for an s-electron will be given by
(a) +
p 2
h
.
2
1
(b) zero
(c)
p 2
h
(d) 2
p 2
h
7. Which orbital of carbon can absorb photon but
not emit it
(a) 1 s (b) 2 s
(c) 3 p (d) 2 p
8. Brackett series are produced when the electrons
from the outer orbits jump to
(a) 2
nd
orbit (b) 3
rd
orbit
(c) 4
th
orbit (d) 5
th
orbit
9. The spectrum of He is expected to be similar to
that of
(a) H (b) Na
(c) He
+
(d) Li
+
10. In Bohr series of lines of hydrogen spectrum the
third line from the red end corresponds to
which one of the following inter–orbit jumps of
the electron for Bohr orbits is an atom of
hydrogen
(a) 3 ? 2 (b) 5 ? 2
(c) 4 ? 1 (d) 2 ? 5
11. In hydrogen atom, energy of first excited state is
–3. 4 eV. Then find out the KE of the same orbit
of hydrogen
(a) + 3.4 eV (b) + 6.8 eV
(c) – 13.6 eV (d) + 13.6 eV
12. The energy of an electron in nth orbit of
hydrogen atoms is
(a) eV
n
6 . 13
4
(b) eV
n
6 . 13
3
(c) eV
n
6 . 13
2
(d) eV
n
6 . 13
13. The value of the energy for the first excited state
of hydrogen atom will be
(a) –13.6 eV (b) –3.40 eV
(c) –1.51 eV (d) –0.85 eV
14. The wavelength associated with a golf ball
weighing 200 g and moving at a speed of 5 m/h
is of the order
(a) 10
–10
m (b) 10
–20
m
(c) 10
–30
m (d) 10
–40
m
15. Number of neutrons in nitride ion (N
-3
)
(a) 4 (b) 5
(c) 6 (d) 7
16. The uncertainty in the position of an electron
(mass = 9.1 x 10
–28
g) moving with a velocity of
3.0 x 10
4
cm s
–1
accurate upto 0.011% will be
(a) 1.92 cm (b) 7.68 cm
(c) 0.175 cm (d) 3.84 cm
17. The uncertainty in the momentum of an electron
is 1.0 x 10
–5
kg ms
–1
. The uncertainty in its
position will be (h = 6.62 x 10
–34
kg m
2
s
–1
)
(a) 1.05 x 10
–26
m (b) 1.05 x 10
–28
m
(c) 5.27 x 10
–30
m (d) 5.25 x 10
–28
m
18. Which of the following is possible
n ? m
l
m
s
(a) 3 2 1 0
(b) 3 0 0 –
2
1
(c) 1 2 2
2
1
(d) 1 0 1
2
1
19. The total number of orbitals in a shell with
principal quantum number ‘n’ is
(a) 2n (b) 2n
2
(c) n
2
(d) n
20. Which one of the following set of quantum
numbers is not possible for 4 p electron
(a) n = 4, ? = 1, m = –1, m
S
= +
2
1
(b) n = 4, ? = 1, m = 0, m
S
= +
2
1
(c) n = 4, ? = 1, m = 2, m
S
= +
2
1
(d) n = 4, ? = 1, m = –1, m
S
= –
2
1
21. For a f–orbital, the values of m are
(a) –2, –1, 0, +1, + 2
(b) –3, –2, –1, 0, +1, +2, 3
(c) –1, 0, +1
(d) 0, +1, +2, +3
22. The number of d–electrons retained in Fe
2+
(At.
no. of Fe = 26) ion is
(a) 3 (b) 4
(c) 5 (d) 6
23. If the nitrogen atom had electronic configuration
1s
7
it would have energy lower than that of the
normal ground state configuration 1s
2
2s
2
2p
3
because the electrons would be closer to the
nucleus. Yet 1s
7
is not observed. It violates
(a) Heisenberg’s uncertainty principle
(b) Hund’s rule
(c) Pauli exclusion principle
(d) Bohr postulate of stationary orbits
24. Which of the following ions has the maximum
magnetic moment
(a) Mn
2+
(b) Fe
2+
(c) Ti
2+
(d) Cr
2+
25. Which principle / rule limits the maximum no.
of electrons in an orbital to two
(a) Aufbau principle
(b) Pauli’s exclusion principle
(c) Hund’s rule of max. multiplicity
(d) Heisenberg’s uncertainty principle
Assertion –Reason
In every question a statement of ASSERTION
is followed by a statement of REASON .Mark
the correct answer out of the following choices:
(a) If both ASSERTION and REASON are
true and reason is the correct explanation of
the assertion.
(b) If both ASSERTION and REASON are
true but reason is not the correct explanation of
the assertion
(c) If ASSERTION is true but REASON is
false
(d) If both ASSERTION and REASON are
false.
26. Assertion : An orbital cannot have more than
two electrons
Reason : No two electrons in an atom can have
the same set of all the four quantum numbers.
27. Assertion : Bohr’s theory explains the line
spectrum of He
+
Reason : It explains the line spectrum of
hydrogen and hydrogen like particles
28. Assertion : Balmer lines lie in the visible region.
Reason : Balmer series are obtained when an
electron jumps from any higher energy level to
3
rd
energy level.
29. Assertion :Radius of first Bohr’s orbit of H atom
is 52.9pm
Reason : Radius of nth orbit of H atom (r
n
) =
52.9 × n
2
pm.
30. Assertion : For a given value of m, spin
quantum number (s) can have only two values
i.e., +
2
1
and
2
1
-
Reason : spin quantum number helps to explain
the magnetic properties of the substance .
ANSWERS
ATOMIC STRUCTURE (SET -B) TEST-1
(Medical)
1 D 6 B 11 A 16 C 21 B 26 A
2 C 7 A 12 C 17 C 22 D 27 A
3 A 8 C 13 B 18 B 23 C 28 C
4 C 9 D 14 C 19 C 24 A 29 A
5 D 10 B 15 D 20 C 25 B 30 B
Solutions
1. (D) Atomic orbitals are 4s, 3s, 3p and 3d. (n + ? )
values being 4, 3, 4 and 5. Hence 3d has highest
energy.
2. (C)
3. (A) Z = 11, A = 24. Hence protons = 11 the
neutrons (24 – 11) = 13.
4. (C) Hydride ion H
–
contains two electrons and
He contains two electrons.
5. (D) Planck’s constant is h and angular
momentum =
p 2
nh
hence they have same
dimensions.
6. (B) Angular momentum
p
+
2
h
) 1 ( ? ? . For s
electron ? = 0. Hence answer is 0.
7. (A) 1s in the lowest energy level, it can absorb
and not emit energy.
8. (C) See text for Brackett n
1
= 4, n
2
= 5, 6, 7 etc.
9. (D) Li
+
and He both have two electrons each
10. (B) It corresponds to Balmer. Series n
1
= 2 and n
2
= 5
11. (A) KE =
2
2
n
Z 6 . 13
ev when n = 2 K.E. =
2
2
1 x 6 . 13
12. (C) E
n
=
2
2
n
Z 6 . 13 -
13. (B) E
2
= 40 . 3
) 2 (
6 . 13
2
- =
-
ev
14. (C) ? =
3600
5
x 200 . 0
10 x 63 . 6
mv
h
34 -
= = 2.4 x 10
–30
m
15. (D)
16. (C) ?x. ?p =
p 4
h
or ?x. m ?v =
p 4
h
;
?v =
100
011 . 0
x 3 x 10
4
= 3.3 cms
–1
?x =
3 . 3 x 10 x 1 . 9 x 14 . 3 x 4
10 x 6 . 6
28
27
-
-
= 0.175 cm
17. (C) ?x = = =
? p
-
-
5
34
10 x 14 . 3 x 4
10 x 63 . 6
p x 4
h
5.27 x 10
–30
m
18. (B)
Page 4
ATOMIC STRUCTURE (SET -B) TEST-1
(Medical)
1. Which of the following set of quantum numbers
belong to highest energy
(a) n = 4, ? = 0, m = 0, s = +
2
1
(b) n = 3, ? = 0, m = 0, s = +
2
1
(c) n = 3, ? = 1, m = 1, s = +
2
1
(d) n = 3, ? = 2, m = 1, s = +
2
1
2. Which is not true with respect to cathode rays
(a) A stream of electrons
(b) Charged particles
(c) Move with speed same as that of light
(d) Can be deflected by magnetic fields
3. An element has atomic number 11 and mass
number 24. What does the nucleus contain
(a) 11 protons, 13 neutrons
(b) 11 protons, 13 neutrons, 13 electrons
(c) 13 protons, 11 neutrons
(d) 13 protons, 11 electrons
4. The hydride ion is isoelectronic with
(a) H
+
(b) He
+
(c) He (d) Be
5. Planck’s constant has the same dimensions as
that of
(a) Power
(b) Work
(c) Radiant energy
(d) Angular momentum
6. The orbital momentum for an electron revolving
in an orbit is given by
p
+
2
h
. ) 1 ( ? ? . This
momentum for an s-electron will be given by
(a) +
p 2
h
.
2
1
(b) zero
(c)
p 2
h
(d) 2
p 2
h
7. Which orbital of carbon can absorb photon but
not emit it
(a) 1 s (b) 2 s
(c) 3 p (d) 2 p
8. Brackett series are produced when the electrons
from the outer orbits jump to
(a) 2
nd
orbit (b) 3
rd
orbit
(c) 4
th
orbit (d) 5
th
orbit
9. The spectrum of He is expected to be similar to
that of
(a) H (b) Na
(c) He
+
(d) Li
+
10. In Bohr series of lines of hydrogen spectrum the
third line from the red end corresponds to
which one of the following inter–orbit jumps of
the electron for Bohr orbits is an atom of
hydrogen
(a) 3 ? 2 (b) 5 ? 2
(c) 4 ? 1 (d) 2 ? 5
11. In hydrogen atom, energy of first excited state is
–3. 4 eV. Then find out the KE of the same orbit
of hydrogen
(a) + 3.4 eV (b) + 6.8 eV
(c) – 13.6 eV (d) + 13.6 eV
12. The energy of an electron in nth orbit of
hydrogen atoms is
(a) eV
n
6 . 13
4
(b) eV
n
6 . 13
3
(c) eV
n
6 . 13
2
(d) eV
n
6 . 13
13. The value of the energy for the first excited state
of hydrogen atom will be
(a) –13.6 eV (b) –3.40 eV
(c) –1.51 eV (d) –0.85 eV
14. The wavelength associated with a golf ball
weighing 200 g and moving at a speed of 5 m/h
is of the order
(a) 10
–10
m (b) 10
–20
m
(c) 10
–30
m (d) 10
–40
m
15. Number of neutrons in nitride ion (N
-3
)
(a) 4 (b) 5
(c) 6 (d) 7
16. The uncertainty in the position of an electron
(mass = 9.1 x 10
–28
g) moving with a velocity of
3.0 x 10
4
cm s
–1
accurate upto 0.011% will be
(a) 1.92 cm (b) 7.68 cm
(c) 0.175 cm (d) 3.84 cm
17. The uncertainty in the momentum of an electron
is 1.0 x 10
–5
kg ms
–1
. The uncertainty in its
position will be (h = 6.62 x 10
–34
kg m
2
s
–1
)
(a) 1.05 x 10
–26
m (b) 1.05 x 10
–28
m
(c) 5.27 x 10
–30
m (d) 5.25 x 10
–28
m
18. Which of the following is possible
n ? m
l
m
s
(a) 3 2 1 0
(b) 3 0 0 –
2
1
(c) 1 2 2
2
1
(d) 1 0 1
2
1
19. The total number of orbitals in a shell with
principal quantum number ‘n’ is
(a) 2n (b) 2n
2
(c) n
2
(d) n
20. Which one of the following set of quantum
numbers is not possible for 4 p electron
(a) n = 4, ? = 1, m = –1, m
S
= +
2
1
(b) n = 4, ? = 1, m = 0, m
S
= +
2
1
(c) n = 4, ? = 1, m = 2, m
S
= +
2
1
(d) n = 4, ? = 1, m = –1, m
S
= –
2
1
21. For a f–orbital, the values of m are
(a) –2, –1, 0, +1, + 2
(b) –3, –2, –1, 0, +1, +2, 3
(c) –1, 0, +1
(d) 0, +1, +2, +3
22. The number of d–electrons retained in Fe
2+
(At.
no. of Fe = 26) ion is
(a) 3 (b) 4
(c) 5 (d) 6
23. If the nitrogen atom had electronic configuration
1s
7
it would have energy lower than that of the
normal ground state configuration 1s
2
2s
2
2p
3
because the electrons would be closer to the
nucleus. Yet 1s
7
is not observed. It violates
(a) Heisenberg’s uncertainty principle
(b) Hund’s rule
(c) Pauli exclusion principle
(d) Bohr postulate of stationary orbits
24. Which of the following ions has the maximum
magnetic moment
(a) Mn
2+
(b) Fe
2+
(c) Ti
2+
(d) Cr
2+
25. Which principle / rule limits the maximum no.
of electrons in an orbital to two
(a) Aufbau principle
(b) Pauli’s exclusion principle
(c) Hund’s rule of max. multiplicity
(d) Heisenberg’s uncertainty principle
Assertion –Reason
In every question a statement of ASSERTION
is followed by a statement of REASON .Mark
the correct answer out of the following choices:
(a) If both ASSERTION and REASON are
true and reason is the correct explanation of
the assertion.
(b) If both ASSERTION and REASON are
true but reason is not the correct explanation of
the assertion
(c) If ASSERTION is true but REASON is
false
(d) If both ASSERTION and REASON are
false.
26. Assertion : An orbital cannot have more than
two electrons
Reason : No two electrons in an atom can have
the same set of all the four quantum numbers.
27. Assertion : Bohr’s theory explains the line
spectrum of He
+
Reason : It explains the line spectrum of
hydrogen and hydrogen like particles
28. Assertion : Balmer lines lie in the visible region.
Reason : Balmer series are obtained when an
electron jumps from any higher energy level to
3
rd
energy level.
29. Assertion :Radius of first Bohr’s orbit of H atom
is 52.9pm
Reason : Radius of nth orbit of H atom (r
n
) =
52.9 × n
2
pm.
30. Assertion : For a given value of m, spin
quantum number (s) can have only two values
i.e., +
2
1
and
2
1
-
Reason : spin quantum number helps to explain
the magnetic properties of the substance .
ANSWERS
ATOMIC STRUCTURE (SET -B) TEST-1
(Medical)
1 D 6 B 11 A 16 C 21 B 26 A
2 C 7 A 12 C 17 C 22 D 27 A
3 A 8 C 13 B 18 B 23 C 28 C
4 C 9 D 14 C 19 C 24 A 29 A
5 D 10 B 15 D 20 C 25 B 30 B
Solutions
1. (D) Atomic orbitals are 4s, 3s, 3p and 3d. (n + ? )
values being 4, 3, 4 and 5. Hence 3d has highest
energy.
2. (C)
3. (A) Z = 11, A = 24. Hence protons = 11 the
neutrons (24 – 11) = 13.
4. (C) Hydride ion H
–
contains two electrons and
He contains two electrons.
5. (D) Planck’s constant is h and angular
momentum =
p 2
nh
hence they have same
dimensions.
6. (B) Angular momentum
p
+
2
h
) 1 ( ? ? . For s
electron ? = 0. Hence answer is 0.
7. (A) 1s in the lowest energy level, it can absorb
and not emit energy.
8. (C) See text for Brackett n
1
= 4, n
2
= 5, 6, 7 etc.
9. (D) Li
+
and He both have two electrons each
10. (B) It corresponds to Balmer. Series n
1
= 2 and n
2
= 5
11. (A) KE =
2
2
n
Z 6 . 13
ev when n = 2 K.E. =
2
2
1 x 6 . 13
12. (C) E
n
=
2
2
n
Z 6 . 13 -
13. (B) E
2
= 40 . 3
) 2 (
6 . 13
2
- =
-
ev
14. (C) ? =
3600
5
x 200 . 0
10 x 63 . 6
mv
h
34 -
= = 2.4 x 10
–30
m
15. (D)
16. (C) ?x. ?p =
p 4
h
or ?x. m ?v =
p 4
h
;
?v =
100
011 . 0
x 3 x 10
4
= 3.3 cms
–1
?x =
3 . 3 x 10 x 1 . 9 x 14 . 3 x 4
10 x 6 . 6
28
27
-
-
= 0.175 cm
17. (C) ?x = = =
? p
-
-
5
34
10 x 14 . 3 x 4
10 x 63 . 6
p x 4
h
5.27 x 10
–30
m
18. (B)
19. (C) Number of orbitals with principal quantum
number n = n
2
.
20. (C) For 4p electron n = 4, ? = 1, m = –1, 0 + 1 and
S = 1/2 or –1/2.
21. (B) For f orbital, the values of m are –3, –2, –1, 0,
+1, +2, +3.
22. (D) Fe
2+
1s
2
, 2s
2
p
6
, 3s
2
p
6
d
6
hence 6 electrons
23. (C) Not more than two electrons can be present
in same atomic orbital. This is Paulis exclusion
principle.
24. (A) Mn
2+
(5), Fe
2+
(4), Ti
2+
(2) and Cr
2+
(4), Mn
2+
contains maximum number of unpaired
electrons hence has maximum magnetic
moment.
25. (B) According to Pauli’s exclusion principle the
maximum number of electrons with opposite
spin present in an atomic orbital is two.
26. (a) Both assertion and reason are true and
reason is the correct explanation of assertion.
According to Pauli’s exclusion principle , no
two electrons in an atom can have same set
of all the four quantum numbers. Therefore,
an orbital has two electrons with opposite
spins.
27. (a) Both assertion and reason are true and
reason is correct explanation of assertion.
Bohr’s theory explains the line spectrum of
hydrogen and hydrogen like particles.
Therefore , line spectrum of He
+
( and not
He
2+
, as He
+
is hydrogen like particle) can be
explained by Bohr’s theory
28. (c) Assertion is true but reason is false.
Balmer series are obtained when an electron
jumps from any higher energy level to 2
nd
energy level while Paschen series are
obtained when an electron jumps from any
higher energy level to 3
rd
energy level.
29. (a) Both assertion and reason are true and
reason is the correct explanation of assertion.
r
n
[For H atom] = 0.529 × n
2
(A °) = 52.9 × n
2
(pm)
30. (B) Both assertion and reason are true but reason
is not the correct explanation of assertion
As the electron in an orbital can spin either in
the clockwise direction or in the
anticlockwise direction, so spin quantum
number can have only two values , +
2
1
and -
2
1
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