VMCC CHEMISTRY BY SHUAIB SIR

ATOMIC STRUCTURE
NEET-UG - Chemistry
Time Allowed: 3 hours Maximum Marks: 300

1. In an alpha scattering experiment, few alpha particles rebounded because [4]

a) Most of the space in the atom is occupied b) All the positive charge and mass of the atom
is concentrated in small volume

c) The mass of the atom is concentrated in the d) Positive charge of the atoms very little
centre space

2. 2 × 108 atoms of carbon are arranged side by side. Calculate the radius of carbon atom if the length of this [4]
arrangement is 2.4 cm.

a) 3.0 × 10-11 m b) 6.0 × 10-11 m

c) 6.0 × 10-12 m d) 5.7 × 10-11 m

3. In an atom, the maximum number of electrons in an orbit / principal energy level n is [4]

a) 2n-1 b) 2n2

c) n2 d) 2n

4. Usings s,p,d, and f notation, choose the orbital with n=4, l=3 quantum numbers. [4]

a) 4d b) 4f

c) 4p d) 3d
5. Maximum number of electrons in a subshell with l = 3 and n = 4 is _____. [4]

a) 14 b) 16

c) 32 d) 12
6. Cathode rays or cathode ray particles are: [4]

a) protons b) electrons

c) muons d) neutrons

7. If a cation B3+ has 18 electrons, the atomic number of element B will be [4]

a) 12 b) 21

c) 15 d) 24

8. The energy associated with the first orbit in the hydrogen atom is -2.17 × 10-18 J/atom. What is the energy [4]
associated with the fifth orbit?

a) 3.72 × 10-20Js b) 8.68 × 10-20Js

c) 5.72 × 10-20Js d) 7.72 × 10-20Js

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 9. When an electron from an excited hydrogen atom undergoes the transition from energy level n = 4 to n = 2, the [4]
emission of radiations will give rise to:

a) Paschen series b) Balmer series

c) Brackett series d) Lyman series

10. The number of radial nodes for 3p orbital is __________. [4]

a) 1 b) 4

c) 2 d) 3
11. An atom of an element contains 29 electrons and 35 neutrons. The number of protons are: [4]

a) 30 b) 35

c) 32 d) 29
12. de-Broglie equation is [4]

a) λ = b) =
h mv
λ
mv h

c) λ = hmv d) λ = hv

13. Number of angular nodes for 4d orbital is ________. [4]

a) 1 b) 3

c) 4 d) 2
14. According to quantum mechanics, |ψ|2 (r) the wave function squared gives: [4]

a) probability of finding a neutron b) probability density of finding a proton

c) probability density of finding an electron d) probability of finding an electron

15. In an atom, an electron is moving with a speed of 600m/s with an accuracy of 0.005%. Certainty with which the [4]
position of the electron can be located is (h = 6.6 × 10-34 Js)?

a) 1.92 × 10-3m b) 1.52 × 10-4m

c) 5.10 × 10-3m d) 3.84 × 10-3m

∘

16. Find the energy of the photon which has a wavelength of 0.50 A? [4]

(Hint: h = Planck’s constant = 6.626 × 10-34 J)

a) 0.98 × 10-15 J b) 1.98 × 10-15 J

c) 2.98 × 10-15 J d) 3.98 × 10-15 J

17. A model of atom in which the idea of orbits associated with definite energies was first given by [4]

a) James Chadwick b) J.J. Thomson

c) Neils Bohr d) Rutherford

18. Which of the following is responsible to rule out the existence of definite paths or trajectories of electrons? [4]

a) Aufbau principle. b) Heisenberg’s uncertainty principle

c) Hund’s rule of maximum multiplicity. d) Pauli’s exclusion principle.

19. Correct expression for all series of lines in the hydrogen spectrum is (n1 = 1, 2 , 3...) and n2 = n1 + 1, n1 + 2, ..., [4]

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 and ν̄ is the wave number)

a) ν̄ = 109, 737 (
1
−
1
)
b) ν̄ = 109, 777 (
1
−
1
)
2 2 2 3
n1 n2 n1 n2

c) 1 1 d) 1 1
ν̄ = 109, 677 ( − ) ν̄ = 109, 677 ( − )
4 2 3 2
n1 n2 n1 n2
charge
20. Values of e
[ ] in the categories alpha particle(α) , electron (e) and protons (p) increase in the order: [4]
m
mass

a) α < p < e b) p < e< α

c) α < e < p d) e < α < p

21. Electronic configuration of five elements I, II, III, IV,W V is mentioned below. [4]

In the above configuration element I, II, III, IV and V represent as

a) Ne, F, O, N, C b) O, C, F, Ne, V

c) C, O, N, Ne, F d) C, N, O, F, Ne
22. Cathode rays are discharged under one of the following conditions: [4]

a) at very low pressure and high voltage b) only when the rays become negatively
charged

c) when a certain type of electrode is used d) when a certain type of gas is used
23. An element with mass number 81 contains 31.7 % more neutrons as compared to protons. Assign the atomic [4]
symbol.

a) 81
35
S b) 81
35
Ag

c) 81
35
Cl d) 81
35
Br
24. According to the quantum theoretical model of an atom, each orbital is designated by three quantum numbers [4]
labelled as n, l, and ml. The values these can take are:

a) n = 1,2,3.. b) n = 1,2,3..
l= 0,1,..n; l= 0,1,..n-1;
m = -l,-l+1, ..0,1..l-1, l m = 0,1..l-1, l

c) n = 1, 2, 3.. d) n = 1,2,3..
l = 0, 1,.. n-1; l= 0,1,..n
ml = -l,-l+1, ..0,1..l-1, l m= -l,-l+1, ..0,1

25. Millikan performs oil drop experiment to determine ________. [4]

a) of the neutron b) mass of the electron

e

c) density of the proton d) charge on the electron

26. The total number of atomic orbitals in fourth energy level of an atom is : [4]

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 a) 16 b) 4

c) 8 d) 32
27. Which represents the correct set of four quantum number of a 4d-electron? [4]

a) 4, 2, 1, 0 b) 4, 3, 2, +
1

c) 4, 3, -2, + d) 4, 2, 1, +
1 1

2 2

28. Two electrons occupying the same orbital are distinguished by: [4]

a) principal quantum number b) spin quantum number

c) azimuthal quantum number d) magnetic quantum number

29. Dimensions of Planck’s constant are : [4]

a) energy × distance b) force × time

energy
c) time
d) energy × time
30. Principal quantum number of an atom is related to the [4]

a) Orbital angular momentum b) Orientation of the orbital in space

c) Spin angular momentum d) Size of the orbit

31. Which of the following visible light has the shortest wavelength? [4]

a) Green b) Yellow

c) Indigo d) Orange

32. Atomic radius is of the order of 10-8 cm and nuclear radius is of the order of 10-13 cm. The fraction of atom [4]

occupied by nucleus is:

a) 105 b) 10-15

c) 10-25 d) 10-5

33. When an electron falls to a lower orbit, its energy ________. [4]

a) becomes zero b) decreases

c) remains constant d) increases

34. The correct set of four quantum number for the valence electron of rubidium atom (Z − 37 ) is [4]

a) 5, 1, 0, + b)
1 1
6, 0, 0, +
2 2

c) 5, 0, 0, + d)
1 1
5, 1, 1, +
2 2

35. Maximum number of electrons that can be accommodated in shell with n = 4 are: [4]

a) 32 b) 16

c) 50 d) 72
36. In absence of Pauli exclusion principle, the electronic configuration of Li in ground state may be: [4]

a) 1s3 b) 1s2, 2s1

c) 1s2, 2s1 2p1 d) 1s1, 2s2

37. The electronic configuration of 46Pd is: [4]

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 a) 18 [Kr]4d
10
b) 36[Kr]4d
10

c) 36[Kr]4d 9 1
, 5s d) 36[Kr]4d , 5s
8 2

38. Average atomic mass of magnesium is 24.32 amu. This Mg is composed of 79 mole % of 24Mg and remaining [4]

21 mole % of 25Mg and 26Mg. Calculate the mole % of 25Mg.

a) 11% b) 20%

c) 22% d) 10%

39. The number of d-electrons in Fe2+ (Z = 26) is not equal to that of: [4]

a) p-electrons in Ne (Z = 10) b) d-electrons in Fe (Z = 26)

c) p-electrons in Cl (Z = 17) d) s-electrons in Mg (Z = 12)

40. If λ and λ be threshold wavelength and wavelength of incident light, the velocity of photoelectron ejected from [4]
0

the metal surface is:

−−−−−−−−− −−−−−−−−−
a) √ 2h
( λ0 − λ) b) √
2hc
(
λ0 −λ
)
m
m λλ0

−−−−−−−−−− −−−−−−−−−
c) √ 2h
(
1
−
1
)
d) √
2hc

m
( λ0 − λ)
m λ0 λ

41. Which one of the following is not isoelectronic with O2-? [4]

a) Ti+ b) N3-

c) F- d) Na+

42. What will be the longest wavelength line in Balmer series of spectrum? [4]

a) 556 nm b) 566 nm

c) 656 nm d) 546 nm
43. If n = 6, the correct sequence for filling of electrons will be : [4]

a) ns → np → (n - 1)d → (n - 2)f b) ns → (n - 1)d → (n - 2)f → np

c) ns → (n - 2)f → (n - 1)d → np d) ns → (n - 2)f → np → (n - 1)d

44. Which of the following is not permissible arrangement of electrons in an atom? [4]
−1 −1
a) c = 4, 1 = 0, m = 0, s = 2
b) n = 3, 1 = 2, m = - 2, s = 2

+1 −1
c) n = 5, l = 3, m = 0, s = 2
d) n = 3, l = 2, m = -3, s = 2

45. The energy of an electron in the ground state (n = for He ion is −xJ , then that for an electron in n = [4]
+
1) 2

state for Be 3+
ion in J is

a) -x b)
x
−
9

c) − d)
4
x −4x
9

46. Which of the following statement is (are) correct? [4]

A. The electronic configuration of 24Cr is [Ar]3d5, 4s1.

B. The magnetic quantum number may have a negative value
C. In 47Ag atom, 23 electrons have a spin of one type and 24 of the opposite type
D. All of these

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 a) only (A) b) only (C)

c) only (B) d) only (D)

47. Isotopes of an element have ________. [4]

a) Similar physical but different chemical b) Similar chemical and physical properties
properties

c) Different chemical and physical properties d) Similar chemical but different physical
properties
48. Identify the INCORRECT match between the element and its valence shell configuration. [4]

a) b)
Mn: Zn:

c) d)
Cr: Cu:

49. Two electrons A and B in an atom have the following set of quantum numbers: What is true for A and B: [4]
A : 3, 2, -2,
+1

B : 3, 0, 0,
+1

a) A and B represent same electron b) A has more energy than B

c) A and B have same energy d) B has more energy than A

50. Which one is a WRONG statement? [4]

a) The total orbital angular momentum of an b) The value of m for d z

2 is zero.
electron in s orbital is equal to zero.

c) An orbital is designated by three quantum d) The electronic configuration of N atom is

numbers while an electron in an atom is
designated by four quantum numbers.
51. What transition in the hydrogen spectrum would have the same wavelength as the Balmer transition n = 4 to n = [4]
2 of He+ spectrum?

a) n = 4 to n = 2 b) n = 2 to n = 1

c) n = 4 to n = 1 d) n = 6 to n = 1
52. The region in the electromagnetic spectrum where the Balmer series lines appear is: [4]

a) Visible b) Microwave

c) Infrared d) Ultraviolet
53. The number of angular nodes and radial nodes in 3s orbital are [4]

a) 1 and 0, respectively b) 0 and 2, respectively

c) 3 and 0, respectively d) 0 and 1,respectively

54. The ratio of the difference in energy of electron between the first and second Bohr’s orbits to that between [4]
second and third Bohr’s orbits is:

a) b)
9 27

4 5

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 c) 1

3
d) 4

55. The isoelectronic set of ions is [4]

a) N3-, Li+, Mg2+ and O2- b) F-, Li+, Na+ and Mg2+

c) N3-, O2-, F- and Na+ d) Li+, Na+, O2- and F-

56. The d orbital/s whose lobes lie along the axis is/are [4]
i. dxy
ii. dyz
iii. dzx

iv. d 2
x −y
2

a) (iv) b) (i), (ii), (iii)

c) (i), (ii), (iv) d) (i), (ii)

57. The correct set of quantum numbers for the unpaired electron of the chlorine atom is: [4]

a) n l m b) n l m

2 1 1 3 0 0

c) n l m d) n l m

3 1 1 2 1 0

58. An element has electronic configuration 2, 8, 18, 1. If its atomic weight is 63, then how many neutrons will be [4]
present in its nucleus?

a) 33 b) 30

c) 32 d) 34
59. Which of the following transitions have minimum wavelength? [4]

a) n4 ⟶ n1 b) n2 ⟶ n1

c) n3 ⟶ n1 d) n4 ⟶ n2

60. The electron identified by quantum numbers n and l, [4]

i. n = 4, l = 1
ii. n = 4, l = 0
iii. n = 3,l = 2
iv. n = 3, l = 1
can be placed in order of increasing energy from the lowest to highest:

a) (ii) < (iv) < (i) < (iii) b) (iv) < (ii) < (iii) < (i)

c) (i) < (iii) < (ii) < (iv) d) (iii) < (i) < (iv) < (ii)
61. How many electrons can fit in the orbital for which n = 3 and l = 1? [4]

a) 10 b) 14

c) 6 d) 2

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62. 30
14
Si and 31
15
P have same number of ________. [4]

a) neutrons b) electrons

c) nucleons d) protons
63. The de Broglie wavelength of a ball of mass 76 g moving with a velocity of 10 metres per second is ________. [4]

a) 5 × 10-31 m b) 8.7 × 10-34 m

c) 3 × 10-35 m d) 11 × 10-16 m

64. Possible number of orientations of a subshell is: [4]

a) 2l + 1 b) n2

c) l d) n
65. Which of the following transitions, for a hydrogen atom, emits a photon of lowest energy? [4]

a) Option B b) Option C

c) Option A d) Option D
o

66. The number of photons emitted in 10 hrs by a 60 W sodium lamp is ________. (λ photon = 5893 A) [4]

a) 17.8 × 10-19 b) 17.8 × 1019

c) 6.4 × 10-24 d) 6.4 × 1024

67. What is the maximum number of electrons in an atom that can have quantum numbers n = 4ml = +1? [4]

a) 15 b) 3

c) 6 d) 4
68. The orbital angular momentum of 2p-orbital is x h

2π
units. The value of x is ________. [4]
–
a) √3 b) 1
–
c) 2 d) √2

69. Which one of the following sets of quantum numbers represents an impossible arrangement? [4]

a) n l m s b) n l m s

5 3 0 4 0 0
1 1
−
2 2

c) n l m s d) n l m s

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 3 2 -2 1

2
3 2 -3 1

70. Ψ
2
= 0 represents [4]

a) An orbital b) Angular wave function

c) Wave function d) A node

71. Assertion (A): All isotopes of a given element show the same type of chemical behaviour. [4]
Reason (R): The chemical properties of an atom are controlled by the number of electrons in the atom.

a) Both A and R are true and R is the correct b) Both A and R are true but R is not the
explanation of A. correct explanation of A.

c) A is true but R is false. d) A is false but R is true.

72. Assertion (A): Atomic orbital in an atom is designated by n, l, m1 and ms. [4]
Reason (R): These are helpful in designating electron present in an orbital.

a) Both A and R are true and R is the correct b) Both A and R are true but R is not the
explanation of A. correct explanation of A.

c) A is true but R is false. d) A is false but R is true.

73. Assertion (A): Sodium chloride imparts a yellow colour to Bunsen flame. [4]
Reason (R): Sodium has low ionization energy.

a) Both A and R are true and R is the correct b) Both A and R are true but R is not the
explanation of A. correct explanation of A.

c) A is true but R is false. d) A is false but R is true.

o

74. Assertion (A): The radius of the first orbit of hydrogen atom is 0.529 A. [4]
o
2

Reason (R): Radius for each circular orbit (rn) = 0.529 A ( n

Z
), where n = 1, 2, 3 and Z = atomic number.

a) Both A and R are true and R is the correct b) Both A and R are true but R is not the
explanation of A. correct explanation of A.

c) A is true but R is false. d) A is false but R is true.

75. Assertion (A): A few positively charged α-particles are deflected in Rutherford experiments. [4]
Reason (R): Most of the space in the atom is empty.

a) Both A and R are true and R is the correct b) Both A and R are true but R is not the
explanation of A. correct explanation of A.

c) A is true but R is false. d) A is false but R is true.

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