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ECAT Chemistry Atomic Structure Online Test

Maan AliLast Updated: April 19, 2025

Chemistry Atomic MCQS Online Test

ECAT Chemistry Atomic Chapter Online Test

Total Questions:	86
Time Allowed:	40 Minutes
Total Marks:	86
How to Attempt Test:	Please choose the right Option in MCQ-type question.
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ECAT Chemistry Atomic Test

Page 1 of 86

Chemistry

1. Rutherford’s experiment led to the discovery of

Electron

Nucleus

α -particle

Proton

Page 2 of 86

2. The letters s p d and f are used to represent which quantum numbers

Principal

Magnetic

Spin

Azimuthal

Page 3 of 86

3. Heaviest particle is

Electron

Neutron

Proton

Meson

Page 4 of 86

4. Rutherford’s atomic model suggests the existence of

Nucleus

α -particle

Mesons

Atom

Page 5 of 86

5. Which of the following is not charged particles?

Neutron

Electron

Proton

Hydrogen nucleus

Page 6 of 86

6. Particles are

Positive charged particles

Gamma radiation

Negative charged particles

Beam of neutrons

Page 7 of 86

7. The radius of hydrogen atom in the ground state is 0.53 Å, the radius of ₃Li²⁺ in the similar state is

0.17 Å

1.06 Å

0.265 Å

0.53 Å

Page 8 of 86

8. When electron collide with heavy particles then which of the following is produced?

x-rays

Beta rays

Gamma rays

Alpha rays

Page 9 of 86

9. The absolute charge of an electron is

+ 1.6 x 10¯¹⁹ C

-1.6 x 10¯¹⁹ C

1.6 x 10¯¹⁹ C

16 x 10¯¹⁹ C

Page 10 of 86

10. The radiations emitted form hydrogen filled discharge tube show

Continuous spectrum

Band spectrum

Line spectrum

Absorption spectrum

Page 11 of 86

11. Rutherford’s gold foil experiment showed that most of the α particles passed through the gold foil without any deflection. It indicates that.

The nucleus is concentrated at the center

The nucleus carries positive charge

There is lot of empty space in atom

The nucleus carries the most of the mass

Page 12 of 86

12. Choose the value of the Red berg’s constant among the following among the following

1.007 x 10⁷ m¯¹

1.697 x 10⁷ m¯¹

1.9678 x 10⁷ m¯¹

1.09678 x 10⁷ m¯¹

Page 13 of 86

13. The total number of orbitals in a shell with principal quantum number ‘n’ is

n + 1

2n²

n²

Page 14 of 86

14. The mass of a neutron is times greater than the mass of electron

2000

1840

540

1480

Page 15 of 86

15. The electronic configuration of an atom is 2,8,3, The number of valence electrons in the atom is.

Page 16 of 86

16. The letters S, P, d and f are used to represent which quantum number

Magnetic (m)

Principal (p)

Spin (S)

Angular momentum (I)

Page 17 of 86

17. If Z represents the atomic number and A represents mass number, then the number of electrons in an atom can be computed as

A + Z

Z – A

A – Z

Page 18 of 86

18. When an atom absorbs energy the bonds in the spectrum will appeal which are

Brighter

Hard to locate

Colourless

Darker

Page 19 of 86

19. Millikan used in atomizer

Milk

Oil

Honey

H₂O

Page 20 of 86

20. No two electrons is the same atom can have identical set of four quantum numbers. This statement is known as?

-(n + 1) rule

- Pauli’s Exclusion principle

- Aufbaus rule

- Hund’s rule

Page 21 of 86

21. An α-particle is

A Hydrogen nucleus

A Helium nucleus

An electron

A proton

Page 22 of 86

22. e/m ratio of the canal rays is less than that of cathode rays. The reason is

Greater mass of canal ray particles

Greater charge of the canal ray particles

Greater mass and charge of the canal ray particles

Actually e/m ratio of canal rays is greater than that of the cathode rays

Page 23 of 86

23. In hydrogen spectrum which one of the following series lies in the ultraviolet region?

P fund series

Balmer series

Lymann series

Bracket series

Page 24 of 86

24. X-ray are

High energy electrons

Radio isotopes

Of unknown nature

High energy photons

Page 25 of 86

25. Planks theory says energy is emitted

In continuous manner

Simultaneously

In the form of heat

Discontinuous manner

Page 26 of 86

26. The penetrating power of X-rays depends on their

Frequency

Source

Applied voltage

All of these

Page 27 of 86

27. Excited atoms return to their ground state in

10-9s

10-8s

10-6s

10-10s

Page 28 of 86

28. Space around nucleus where finding of electrons is maximum is

Orbital

Sub shell

Electron cloud

Orbit

Page 29 of 86

29. Radiation emitted by exited atoms is

In the form of continuous waves

Nuclear radiations

In the form of quanta

Ultraviolet radiations

Page 30 of 86

30. When electron jump into orbit 1 then series obtained is

Paschen

Bracket

P fund

Lyman

Page 31 of 86

31. At 200°C hydrogen molecules have velocity 10⁵ cm sec¯¹. The de-Broglie wavelength in this case is approximately

1000 Å

2 Å

10 Å

100 Å

Page 32 of 86

32. The credit of discovering neutron goes to

Langmuir

Rutherford

Austen

Chadwick

Page 33 of 86

33. The ratio of the ionization energy of H and Be³⁺ is

1 : 16

1 : 3

1 : 1

1 : 9

Page 34 of 86

34. The radius of second Bohr’s orbit is

0.053 x 4 nm

0.053/4 nm

0.053 nm

0.053 x 20 nm

Page 35 of 86

35. Ruther fords planet like structure was defective and unsatisfactory because

All

Continuous spectrum

Behavior of electron remain unexplained

Moving e-accelerate towards the nucleus

Page 36 of 86

36. Canal rays are

Negative charged particles

Gamma radiation

Positive charged particles

Beam of neutrons

Page 37 of 86

37. When atom is in the ground state, the electron is present

In the second shell

Nearest to the valence shell

Nearest to the nucleus

In the nucleus

Page 38 of 86

38. Number of neutrons in heavy hydrogen atom is

Page 39 of 86

39. The number of electrons in the M shell of the element with atomic number 24 is

Page 40 of 86

40. The mass of the neutron is of the order of

10¯²⁷ kg

10¯²³ kg

10¯²⁶ kg

10¯²⁴ kg

Page 41 of 86

41. Almost the entire mass of an atom is concentrated in the

Nucleus

Proton

Electrons

Neutrons

Page 42 of 86

42. The maximum number of electrons in a sub-shell for which l = 3 is

Page 43 of 86

43. Positive rays give flash on

ZnS

AgNO₃ plate

AgCl plate

ZnO

Page 44 of 86

44. P fund series are produced in the spectrum of hydrogen atom

When electrons jump down to 5th – orbit

When electrons jump down to 4th – orbit

When electrons jump down to 2nd – orbit

When electrons jump down to 3rd – orbit

Page 45 of 86

45. The quantum number which determines the shape of the orbital is

Principal

Magnetic

Spin

Azimuthal

Page 46 of 86

46. The electronic configuration of an atom/ion can be defined by the following

Pauli’s exclusion principle

Hund’s Rule

All the above

Aufbau principle

Page 47 of 86

47. Charge of electron was measured by

Millikan

Passim

Rutherford

J.J. Thomson

Page 48 of 86

48. Subsidiary quantum number specifies

Nuclear stability

Shape of orbital

Orientations of orbital

Size of orbital

Page 49 of 86

49. During a chemical reaction, atomic number

Changed

Remains same

Changes and then is restored

Changes alternately

Page 50 of 86

50. The magnetic quantum number has value limited directly by the value of

Angular

Spin

Both a and b

Principal quantum number

Page 51 of 86

51. Which one of the following will have the maximum charge/mass ratio?

Neutron

α particle

Electron

Proton

Page 52 of 86

52. A 4f orbital has

Two nodes

Three node

One node

Four nodes

Page 53 of 86

53. The maximum number of electrons that can be accommodated by p – orbital is?

– 6

– 2

– 10

– 14

Page 54 of 86

54. The number of spherical nodes in 3p orbitals are

Two

Non

Three

One

Page 55 of 86

55. For which of the following sets of quantum numbers an electron will have the highest energy?

3, 2, 1, ½

4, 2, -1, ½

4, 1, 0, -1/2

5, 0, 0, ½

Page 56 of 86

56. The magnetic quantum number (QN) has its values determined directly by the value of

Azimuthal (QN)

Spin (QN)

Both a and b

Principal (QN)

Page 57 of 86

57. Where does the cathode rays get deflected?

None of these

A magnetic field only

Both electric and magnetic field

An electric field only

Page 58 of 86

58. Which one is not true about cathode rays

Cannot ionized

Heat up

Cast shadow

9.11 x 10¯³¹ kg

Page 59 of 86

59. Which of the air pressures is appropriate for the production of cathode rays in the discharge tube?

0.001 cm Hg

1 mm Hg

1 cm Hg

0.001 mm Hg

Page 60 of 86

60. Quantum number tells the energy of electron

Page 61 of 86

61. Plank’s theory says energy is emitted

Never emit energy

Discontinuous manner

In continuous manner

Simultaneously

Page 62 of 86

62. Positive particles in discharge tube is produced by ionization of gas molecules which is caused by

Gas molecules produce X – rays

Gas molecules are at high temperature

Cathode rays remove the electrons from gas molecules

Gas molecules collide with anode

Page 63 of 86

63. When X-rays are passed through successive aluminum sheets what happens to their thickness?

It remains same

Increases

Sometimes increases and sometimes decreases

It decreases

Page 64 of 86

64. Photon of highest frequency will be absorbed when transition takes place from

4th to 5th orbit

2nd to 5th orbit

1st to 5th orbit

3rd to 5th orbit

Page 65 of 86

65. A fast moving neutron can eject from nitrogen

Electrons

Β-rays

r-rays

X-rays

Page 66 of 86

66. Pressure in gas discharge tube was kept

0.01 torr

1 torr

0.1 torr

10 torr

Page 67 of 86

67. The value of e/m ratio of electron is

9.1095 x 10¯³¹ C/kg

6.02 x 10²³ C/kg

1.7588 x 10²⁰ C/kg

1.7588 x 10¹¹ C/kg

Page 68 of 86

68. The electron in an atom

Has fixed space around the nucleus

Is stationary in various energy levels

Moves around its nucleus in definite energy levels

Moves randomly around the nucleus

Page 69 of 86

69. Hydrogen atom does not emit X-rays because

Its energy levels are too far apart

It is too small in size

Its energy levels are too close to each other

It has a single electron

Page 70 of 86

70. Wavelength of electron was verified by

Davison and Garner

Einstein

Moseley

Garter

Page 71 of 86

71. Ionization energies of the elements of group A are greater than those of Group VI A. The reason is that

Group V A elements half – filled atomic orbitals

Group VI A elements have greater shielding effect

Group V A element have less elector negativity

Group V A elements have greater shielding effect

Page 72 of 86

72. The number of neutrons in the element ⁹₄Be is

Page 73 of 86

73. The symbol of the element whose atoms have the outer most electronic configuration 2s² 2p³ is

Page 74 of 86

74. The proton is heavier than an electron by

1840 times

1850 times

100 times

1000 times

Page 75 of 86

75. The relationship between energy of a photon of light and its frequency is given by

De-Broglie’s dual nature of atom

Plank’s quantum theory

Bohr’s model

Rutherford’s atomic model

Page 76 of 86

76. Spectrum is produced due to

All have little contribution

Different intensities

Different colours

Different wavelength

Page 77 of 86

77. Total number of series in hydrogen spectrum is

Six

Four

Three

Five

Page 78 of 86

78. In an X-ray tube electrons each of charge e are accelerated through V potential difference allowed to hit a metal target. The wavelength of the X-rays emitted is

Impossible to predict

eV/h

he/Ve

he/ev

Page 79 of 86

79. The K, L and M shells of an atom are full. Its atomic number is

Page 80 of 86

80. An atom has a mass number of 23 and atomic number 11. The number of protons are

Page 81 of 86

81. When electrons revolve in stationary orbits,

There is no change in energy level

There is increase in energy

They become stationary

They are gaining kinetic energy

Page 82 of 86

82. The valence orbital configuration of an element with atomic number 23 is

3d⁵

3d³, 4s²

3d², 4s², 4p¹

3d³, 4s¹, 4p¹

Page 83 of 86

83. The mass of the atom is determined by

Neutrons

Electron and neutron

Neutron and proton

Electron

Page 84 of 86

84. P fund series are produced in the spectrum of hydrogen atom

When electron jump to 3-orbit

When electron jump to 4-orbit

When electron jump to 2-orbit

When electron jump to 5-orbit

Page 85 of 86

85. Millikan determined the charge on electron in oil drop experiment. It value is

1.602 x 10¯²³ C

1.602 x 10¯¹⁹ C

6.625 x 10¯³⁴ C

1.603 x 10¯²³ C

Page 86 of 86

86. Mass number is equal to the

Number of protons + number of electrons

Number of electrons

Number of protons + number of neutrons

Number of neutrons + number of electrons

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Maan AliLast Updated: April 19, 2025

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ECAT Chemistry Atomic Structure Online Test

Chemistry Atomic MCQS Online Test

ECAT Chemistry Atomic Chapter Online Test

ECAT Chemistry Atomic Test

Chemistry

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Chemistry Atomic MCQS Online Test

ECAT Chemistry Atomic Chapter Online Test

ECAT Chemistry Atomic Test

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