Download CHAPTER STRUCTURE OF ATOM

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CHAPTER
STRUCTURE OF ATOM
1. The spectrum of He is expected to be similar
to that [1988]
(a) H
(b) Li+
(c) Na
(d) He+
Ans: (b)
2. The number of spherical nodes in 3p orbitals
are [1988]
(a) one
(b) three
(c) none
(d) two
Ans: (a)
3. If r is the radius of the first orbit, the radius of
nth orbit of H-atom is given by [1988]
(a) rn2
(b) rn
(c) r/n
(d) r2 n2
Ans: (a)
4. Which of the following statements do not
form a part of Bohr’s model of hydrogen atom?
[1989]
(a) Energy of the electrons in the orbits are
quantized
(b) The electron in the orbit nearest the nucleus
has the lowest energy
(c) Electrons revolve in different orbits around
the nucleus
(d) The position and velocity of the electrons in
the orbit cannot be determined simultaneously.
Ans: (d)
5. Number of unpaired electrons in N 2+ is
[1989]
(a) 2
(b) 0
(c) 1
(d) 3
Ans: (c)
6. The maximum number of electrons in a
subshell is given by the expression [1989]
(a) 4l – 2
(b) 4l + 2
(c) 2l + 2
Chapterwise Previous year Qs
(d) 2n2
Ans: (b)
7. The total number of electrons that can be
accommodated in all the orbitals having
principal quantum number 2 and azimuthal
quantum number 1 is [1990]
(a) 2
(b) 4
(c) 6
(d) 8
Ans: (c)
8. An ion has 18 electrons in the outermost
shell, it is [1990]
(a) Cu+
(b) Th4+
(c) Cs+
(d) K+
Ans: (a)
9. In a given atom no two electrons can have the
same values for all the four quantum numbers.
This is called [1991]
(a) Hund’s Rule
(b) Aufbau principle
(c) Uncertainty principle
(d) Pauli’s Exclusion principle.
Ans: (d)
10.
[1991]
(a) 2
(b) 6
(c) 0
(d) 14
Ans: (d)
11. The order of filling of electrons in the
orbitals of an atom will be [1991]
(a) 3d, 4s, 4p, 4d, 5s
(b) 4s, 3d, 4p, 5s, 4d
(c) 5s, 4p, 3d, 4d, 5s
(d) 3d, 4p, 4s, 4d, 5s
Ans: (b)
12. The energy of an electron in the n the Bohr
orbit of hydrogen atom is [1992]
(a)
13
(b)
(c)
(d)
Ans: (c)
13. Which of the following species has four lone
pairs of electrons? [1993]
(a) I
(b) O–
(c) Cl–
(d) He
Ans: (b)
14. If ionization potential for hydrogen atom is
13.6 eV, then ionization potential for He + will be
[1993]
(a) 54.4 eV
(b) 6.8 eV
(c) 13.6 eV
(d) 24.5 eV
Ans: (a)
15. [1994]
(a)
(b)
(c)
(d)
Ans: (b)
16. Which of the following is never true for
cathode rays? [1994]
(a) They possess kinetic energy
(b) They are electromagnetic waves
(c) They produce heat
(d) They produce mechanical pressure.
Ans: (b)
17. The electron was shown experimentally to
have wave properties by [1994]
(a) de Broglie
(b) Davisson and Germer
(c) N. Bohr
(d) Schrodinger.
Ans: (b)
18. 18 When an electron of charge e and mass
m moves with a velocity v about the nuclear
charge Ze is circular orbit of radius r, the
Chapterwise Previous year Qs
potential energy of the electrons is given by
[1994]
(a) Ze2/r
(b) -Ze2/r
(c) Ze2/2r
(d) mv2/r
Ans: (b)
19. In the photo-electron emission, the energy
of the emitted electron is [1994]
(a) greater than the incident photon
(b) same as than of the incident photon
(c) smaller than the incident photon
(d) proportional to the intensity of incident
photon.
Ans: (c)
20. If electron has spin quantum number + 2/1
and a magnetic quantum number -1, it cannot be
present in [1994]
(a) d-orbital
(b) f-orbital
(c) p-orbital
(d) s-orbital.
Ans: (d)
21.
[1995]
(a)
(b)
(c)
(d)
Ans: (a)
22. Uncertainty in position of an electron (mass
= 9.1 × 10–28 g) moving with a velocity of 3 × 104
cm/s accurate upto %0.001 will be (use h/4 π)
in uncertainty expression where h = 6.626 ×10–
27 erg-second) [1995]
(a) 1.93 cm
(b) 3.84 cm
(c) 5.76 cm
(d) 7.68 cm
Ans: (a)
23. The orbitals are called degenerate when
[1996]
(a) they have the same wave functions
(b) they have the same wave functions but
different energies
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(c) they have different wave functions but same
energy
(d) they have the same energy
Ans: (d)
24. The momentum of a particle having a de
Broglie wavelength of 10–17 metres is (Given h =
6.625 × 10–34 Js) [1996]
(a) 3.3125 × 10–7 kg ms– 1
(b) 26.5 × 10–7 kg ms– 1
(c) 6.625 × 10–17 kg ms– 1
(d) 13.25 × 10–17 kg ms–1
Ans: (c)
25. The ion that is isoelectronic with CO is
[1997]
(a) CN –
(b) O2 +
(c) O2–
+
(d) N 2
Ans: (a)
26.
[1998]
(a) 0.13
(b) 1.06
(c) 4.77
(d) 2.12
Ans: (d)
27. The position of both, an electron and a
helium atom is known within 1.0 nm. Further
the momentum of the electron is known within
5.0 × 10–26 kg ms– . 1The minimum uncertainty in
the measurement of the momentum of the
helium atom is [1998]
(a) 50 kg ms– 1
(b) 80 kg ms– 1
(c) 8.0 × 10–26 kg ms– 1
(d) 5.0 × 10–26 kg ms–1
Ans: (d)
28. According to Bohr’s theory the energy
required for an electron in the Li 2+ ion to be
emitted from n = 2 state is (given that the
ground state ionization energy of hydrogen
atom is 13.6 eV) [1999]
(a) 61.2 eV
(b) 13.6 eV
(c) 30.6 eV
Chapterwise Previous year Qs
(d) 10.2 eV
Ans: (c)
29. If the energy of a photon is given as: = 3.03
× 10–19 J then, the wavelength of the photon is:
[2000]
(a) 6.56 nm
(b) 65.6 nm
(c) 656 nm
(d) 0.656 nm
Ans: (c)
30. Set of isoelectronic species is [2000]
(a) N 2,CO2,CN -,O
(b) N,H 2S,CO
(c) N 2 , CO, CN - , O2+2
(d) Ca,Mg,Cl
Ans: (c)
31. The following quantum numbers are
possible for how many orbital n = 3, l = 2, m =
+2? [2001]
(a) 1
(b) 3
(c) 2
(d) 4
Ans: (a)
32. Which of the following is isoelectronic?
[2002]
(a) CO2, NO2
(b) NO2– , CO2
(c) CN – , CO
(d) SO2, CO2
Ans: (c)
33. In hydrogen atom, energy of first excited
state is –3.4 eV. Find out KEof the same orbit of
Hydrogen atom [2002]
(a) + 3.4 eV
(b) + 6.8 eV
(c) – 13.6 eV
(d) + 13.6 eV
Ans: (a)
34. The value of Planck's constant is 6.63 × 10–34
Js. The velocity of light is 3.0 × 108 m s– . 1Which
value is closest to the wavelength in nanometers
of a quantum of light with frequency of 8 × 1015
s–1? [2003]
(a) 3 × 107
(b) 2 × 10–25
15
(c) 5 × 10– 18
(d) 4 × 101
Ans: (d)
35. The ions O2– , F – , Na+, Mg2+ and Al3+ are
isoelectronic. Their ionic radii show [2003]
(a) Adecrease from O2– to F– and then increase
from Na+ to Al 3+
(b) Asignificant increase from O2– to Al3+
(c) Asignificant decrease from O2– to Al3+
(d) An increase from O2– to F – and then decrease
from Na+ to Al3+
Ans: (c)
36. The frequency of radiation emitted when
the electron falls from n = 4 to n = 1 in a
hydrogen atom will be (Given ionization energy
of H=2.18 ×10–18 J atom –1 and h = 6.625 × 10–34
Js) [2004]
(a)
(b)
(c)
(d)
Ans: (c)
37. The energy of second Bohr orbit of the
hydrogen atom is 328 kJmol1; hence the energy
of fourth Bohr orbit would be: [2005]
(a) 41- kJmol- 1
(b) 82- kJmol- 1
(c) 164- kJmol- 1
(d) 1312- kJmol- 1
Ans: (b)
38. Given: The mass of electron is 9.11 × 10–31
kg Plank constant is 6.626 × 10–34 Js,
the uncertainty involved in the measurement of
velocity within a distance of 0.1 A is [2006]
(a) 5.79 × 107 ms– 1
(b) 5.79 × 108 ms– 1
(c) 5.79 × 105 ms– 1
(d) 5.79 × 106 ms–1
Ans: (d)
39. The orientation of an atomic orbital is
governed by [2006]
(a) Spin quantum number
Chapterwise Previous year Qs
(b) Magnetic quantum number
(c) Principal quantum number
(d) Azimuthal quantum number
Ans: (b)
40.
[2007]
(a) , (ii) , (iii) and (iv)
(b) (ii) , (iv) and
(c) and (iii)
(d) (ii) , (iii) and (iv)
Ans: (b)
41. If uncertainty in position and momentum
are equal, then uncertainty in velocity is: [2008]
(a)
(b)
(c)
(d)
Ans: (a)
42. The measurement of the electron position if
associated with an uncertainty in momentum,
which is equal to 1 × 10–18 g cm s–1. The
uncertainty in electron velocity is, (mass of an
electron is 9 × 10–28 g) [2008]
(a) 1 × 109 cm s– 1
(b) 1 × 106 cm s– 1
(c) 1 × 105 cm s– 1
(d) 1 × 1011 cm s–1
Ans: (a)
43. The energy absorbed by each molecule (A 2)
of a substance is 4.4 × 10–19 Jand bond energy
per molecule is 4.0 × 10–19 J. The kinetic energy
of the molecule per atom will be: [2009]
(a) 2.2 × 10–19 J
16
(b) 2.0 × 10–19 J
(c) 4.0 × 10–20 J
(d) 2.0 × 10–20 J
Ans: (d)
44. Maximum number of electrons in a subshell
of an atom is determined by the following:
[2009]
(a) 2 l + 1
(b) 4 l – 2
(c) 2 n2
(d) 4 l + 2
Ans: (d)
45. Which of the following is not permissible
arrangement of electrons in an atom? [2009]
(a) n = 5, l = 3, m = 0, s = + 2/1
(b) n = 3, l = 2, m = – 3, s = – 2/1
(c) n = 3, l = 2, m = – 2, s = – 2/1
(d) n = 4, l = 0, m = 0, s = – 2/1
Ans: (b)
46.
According to MOtheory which of the
following lists ranks the nitrogen species in
terms of increasing bond order? [2010]
(a)
(b)
(c)
(d)
Ans: (a)
47. Which one of the following species does not
exist under normal conditions? [2010]
(a) Be2+
(b) Be2
(c) B 2
(d) Li2
Ans: (b)
48. A 066. kg ball is moving with a speed of 100
m/s. The associated wavelength will be ( h=6.6 ×
10-34 Js) [2011]
(a) 1.0 u 10–32m
(b) 6.6 u 10–32m
(c) 6.6 u 10–34m
(d) 1.0 u 10–35m
Ans: (d)
Chapterwise Previous year Qs
49. The total number of atomic orbitals in fourth
energy level of an atom is: [2011]
(a) 8
(b) 16
(c) 32
(d) 4
Ans: (b)
50. Which of the following has the minimum
bond length? [2011]
(a) O2 +
(b) O2 –
(c) O22–
(d) O2
Ans: (a)
51.
[2011]
(a)
(b)
(c)
(d)
Ans: (b)
52. If n = 6, the correct sequence for filling of
electrons will be:[2011]
(a)
(b)
(c)
(d)
Ans: (a)
53. According to the Bohr Theory, which of the
following transitions in the hydrogen atom will
give rise to the least energetic photon? [2011 M]
[2011]
(a) n = 6 to n = 1
(b) n = 5 to n = 4
(c) n = 6 to n = 5
(d) n = 5 to n = 3
Ans: (c)
54. The pairs of species of oxygen and their
magnetic behaviours are noted below. Which of
the following presents the correct description?
[2012]
(a)
17
Chapterwise Previous year Qs
(b)
n = 3, l = 1 and m = –1 [2013]
(c)
(a) 6
(b) 4
(c) 2
(d) 10
Ans: (c)
(d)
Ans: (c)
55. Maximum number of electrons in a subshell
with: l = 3 and n = 4 is: [2012]
(a) 14
(b) 16
(c) 10
(d) 12
Ans: (a)
56. The correct set of four quantum numbers
for the valence electron of rubidium atom (Z=
)37 is [2012]
(a) 5, 1, + 2/1
(b) 6, 0, 2/1 + 0
(c) 5, 0, 2/1 + 0
(d) 5, 1, 2/1 + 0
Ans: (c)
57. The orbital angular momentum of a pelectron is given as: [2013]
(a)
60.
[2013]
(a) Larger the value of n, the larger is the orbit
radius.
(b) Equation can be used to calculate the change
in energy when the electron changes orbit.
(c) For n = 1, the electron has a more negative
energy than it does for n = 6 which mean that
the electron is more loosely bound in the
smallest allowed orbit.
(d) The negative sign in equation simply means
that the energy or electron bound to the nucleus
is lower than it would be if the electrons were at
the infinite distance from the nucleus.
Ans: (c)
61.
(b)
(c)
[2013]
(d)
Ans: (a)
(a)
58. The value of Planck’s constant is 6.63 × 10–
(b)
Js. The speed of light is 3 × 1017 nm s– . 1Which
value is closest to the wavelength in nanometer
of a quantum of light with frequency of 6 × 1015
s–1? [2013]
(a) 25
(b) 50
(c) 75
(d) 10
Ans: (b)
34
59. What is the maximum numbers of electrons
that can be associated with the following set of
quantum numbers?
(c)
(d)
Ans: (b)
SOLTIONS
1.
2.
18
Chapterwise Previous year Qs
3.
4.
14.
5.
6.
7.
8.
15.
16.
17.
9.
10.
18.
11.
19.
20.
12.
21.
13.
19
Chapterwise Previous year Qs
22.
27.
28.
29.
23.
24.
30.
25.
31.
26.
20
Chapterwise Previous year Qs
32.
34.
40.
35.
41.
36.
37.
42.
38.
43.
44.
39.
45.
21
46.
Chapterwise Previous year Qs
57.
47.
48.
49.
50.
58.
51.
59.
52.
53.
54.
55.
56.
60.
Energy of an electron at infinite distance from
the nucleus is zero. As an electron approaches
the nucleus, the electronattraction increases
and hence the energy of electron decreases and
thus becomes negative. Thus as the value of n
decreases, i.e. lower the orbit is, more negative
is the energy of the electron in it.
61.