Atomic Structure

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1. ‘Atomic theory’ of the matter was given by
(A) Avogadro (B) Dalton
(C) Newton (D) Pascal
Ans. (B)

2. Atomic size is of the order of—
(A) 10–8 cm (B) 10–10 cm
(C) 10–13 cm (D) 10–6 cm
Ans. (A)

3. The fundamental particles that are composed on atoms –
(A) Proton, electron, meson
(B) Proton, electron, photon
(C) Proton, electron, neutron
(D) Proton, electron, deuteron
Ans. (C)

4. The size of the nucleus is measured in:
(A) amu (B) angstrom
(C) cm (D) Fermi
Ans. (D)

5. The radius of an atomic nucleus is of the order of—
(A) 10–10 cm (B) 10–13 cm
(C) 10–15 cm (D) 10–8 cm
Ans. (B)

6. Nucleus of an atom consists of.
(A) Proton (B) Neutron
(C) Proton and Neutron
(D) Electron, Proton and Neutron
Ans. (C)

7. Which of the following is not a nucleon?
(A) Proton (B) Electron
(C) Neutron (D) Positron
Ans. (B)

8. According to Rutherford’s atomic model, the electron inside an atom are–
(A) Stationary (B) Centralized
(C) Non-stationary (D) None of these
Ans. (C)

9. Rutherford’s -scattering experiment related to the size of the—
(A) Nucleus (B) Atom
(C) Electron (D) Neutron
Ans. (A)

10. Discovery of the nucleus of an atom was due to the experiment carried out by—
(A) Bohr (B) Rutherford
(C) Moseley (D) Thomson
Ans. (B)

11. The atomic number of carbon is 6 and its atomic
mass is 12. How many are there protons in the nucleus of carbon?
(A) 6 (B) 12
(C) 18 (D) zero
Ans. (A)

12. When Helium atom loses electron, then it becomes–
(A) Proton (B) Positive Helium ion
(C) Negative Helium ion (D) Alpha Particle
Ans. (B)

13. Which of the following particle is negatively charged?
(A) Proton (B) Neutron
(C) Positron (D) Electron
Ans. (D)

14. The absolute value of charge on the electron was determined by—
(A) J.J. Thomson (B) R.A. Millikan
(C) Rutherford (D) Chadwick
Ans. (B)

15. Electrons move around the nucleus in
(A) Translatory (B) Spin
(C) Orbital (D) Vibrational
Ans. (C)

16. An atom has 2 electrons in K-shell, 8 electrons
in L-shell and 6 electrons in M – shell. The number of s – electrons present in that element is –
(A) 6 (B) 5
(C) 7 (D) 10
Ans. (A)

17. The proton is heavier than an electron by
(A) 187 times (B) 1837 times
(C) 3837 times (D) 2827 times
Ans. (B)

18. CN– ion is isoelectronic with –
(A) N2 (B) CO
(C) both a & b (D) None
Ans. (C)

19. Which of the following is the maximum number of electrons that can be present in an M-shell?
(A) 2 (B) 8
(C) 18 (D) 32
Ans. (C)

20. Which among the following will be a negative ion?
(A) If it has more electrons than protons
(B) If it has more electrons than neutrons
(C) If it has more protons than electrons
(D) If it has more protons than neutrons
Ans. (A)

21. Electrons in the highest energy level of an atom are called ________.
(A) Valence protons (B) Orbital protons
(C) Valence electrons (D) Orbital electrons
Ans. (C)

22. Fe has 26 protons in its nucleus. What are the
number of electrons in Fe2+ (II) ion?
(A) 24 (B) 26 (C) 28 (D) 13
Ans. (A)

23. Number of p-electrons in bromine atom:
(A) 12 (B) 15
(C) 7 (D) 17
Ans. (D)

24. Which of the following has maximum Mass?
(A) Electron (B) Proton
(C) Neutron (D) Nucleus of Hydrogen
Ans. (C)

25. The mass of proton and mass of _____ is the same.
(A) Neutron (B) Electron
(C) Isoprone (D) Alpha particle
Ans. (A)

26. The nuclear particle having no mass and no
charge, but only spin is
(A) Proton (B) Neutrino
(C) Meson (D) Electron
Ans. (B)

27. Who is awarded by Nob le prize for the
discovery of Neutron?
(A) Chadwick (B) Rutherford
(C) Neil Bohr (D) Roentgen
Ans. (A)

28. The electronic configuration of a dipositive ion
M²+ is 2, 8, 14 and its atomic mass is 56. The
number of neutrons in the nucleus would be:
(A) 30 (B) 32 (C) 34 (D) 42
Ans. (A)

29. The triad of nuclei is isotone in :
(A) 6C14 , 7N15, 9F17 (B) 6C12 , 7N14 , 9F18
(C) 6C14 , 7N14 , 9F17 (D) 6C14 , 7N14 , 9F19
Ans. (A)

30. The unrelated member of the following group is
(A) Helium ion (B) Neutron
(C) Proton (D) Cyclotron
Ans. (D)

31. The antiparticle of an electron is
(A) Positron (B) Proton
(C) Alpha particle (D) Beta particle
Ans. (A)

32. Which two basic forces are able to provide an attractive force between two neutrons?
(A) Gravitational and Electrostatic forces
(B) Some other forces
(C) Gravitational and Nuclear forces
(D) Electrostatic and Nuclear forces
Ans. (C)

33. Cathode rays are–
(A) Stream of a-particles
(B) Stream of electrons
(C) Electromagnetic waves
(D) Radiations
Ans. (B)

34. When cathode rays strike a target of high
atomic weight, they give rise to
(A) a-rays (B) b and g rays
(C) X-rays (D) Positive rays
Ans. (C)

35. J.J. Thomson proposed a model which is
generally called ……….. model.
(A) Cream and cake (B) Plum and pudding
(C) Plum and cake (D) Cream and pudding
Ans. (B)

36. Match column-I and column-II
Column-I Column-II
A. Thomson model 1. Dual nature of electron
B. Rutherford model 2. Nuclear theory
C. Bohr’s model 3. Plum pudding model
D. De-Broglie theory 4. Concept of quantization of energy
(A) A–3, B–4, C–2, D–1
(B) A–2, B–4, C–1, D–2
(C) A–2, B–1, C–3, D–4
(D) A–3, B–2, C–4, D–1
Ans. (D)

37. Atomic number of an atom gives the number of
which of the following?
(A) Electrons (B) Protons
(C) Neutrons (D) Neutrons and Protons
Ans. (B)

38. Which of the properties of the element is a whole number?
(A) Atomic mass (B) Atomic number
(C) Atomic radii (D) Atomic volume
Ans. (B)

39. Element having atomic number 29 is related to –
(A) s-Block (B) d-Block
(C) p-Block (D) f-Block
Ans. (B)

40. Electronic configuration of calcium atom can be written as:
(A) [Ne], 4p2 (B) [Ar], 4s2
(C) [Ne], 4s2 (D) [Kr], 4p2
Ans.(B)

41. The electronic configuration of chromium (Z =24 ) is
(A) [Ne] 3s23p63d4, 4s2 (B) [Ne] 3s23p63d5, 4s1
(C) [Ne] 3s23p63d1, 4s2 (D) [Ne] 3s23p6 , 4s24p4
Ans. (B)

42. Two elements X and Y are isotonic having
atomic weight 54 and 56 respectively. If the
atomic number of X is 26, then the atomic number of Y is :
(A) 26 (B) 27
(C) 28 (D) 30
Ans (C)

43. What is the formula of potassium ion in the noble state?
(A) K+ (B) K2+ (C) K2- (D) K–
Ans. (A)

44. Atomic Number of Hydrogen is _______.
(A) 4 (B) 3
(C) 2 (D) 1
Ans. (D)

45. Atomic number of which of the following
elements is greater than that of Magnesium
(A) Neon (B) Fluorine
(C) Sodium (D) Aluminium
Ans. (D)

46. Atomic number of which of the following elements is greater than that of Aluminium?
(A) Phosphorous (B) Neon
(C) Magnesium (D) Sodium
Ans. (A)

47. Atomic number of which of the following
elements is greater than that of Phosphorous?
(A) Aluminium (B) Silicon
(C) Chlorine (D) Magnesium
Ans. (C)

48. Atomic number of which of the following elements is greater than that of Neon?
(A) Oxygen (B) Magnesium
(C) Nitrogen (D) Boron
Ans. (B)

49. Atomic number of which of the following
elements is greater than that of silicon ______
(A) Aluminium (B) Sulphur
(C) Magnesium (D) Sodium
Ans. (B)

50. Atomic number of which of the following
elements is greater than that of Zinc
(A) Copper (B) Iron
(C) Chromium (D) Bromine
Ans. (D)

51. Atomic number of which of the following
elements is greater than that of Iodine
(A) Silver (B) Bromine
(C) Platinum (D) Zinc
Ans. (C)

52. Atomic number of which of the following
elements is greater than the of potassium.
(A) Sulphur (B) Chlorine
(C) Calcium (D) Argon
Ans. (C)

53. Atomic number of which of the following
elements is greater than that of Calcium?
(A) Chlorine (B) Argon
(C) Sulphur (D) Scandium
Ans. (D)

54. Atomic number of which of the following elements is greater than that of Chlorine
(A) Potassium (B) Sulphur
(C) Aluminium (D) Phosphorous
Ans. (A)

55. Atomic number of which of the following elements is greater than that of Copper?
(A) Iron (B) Chromium
(C) Zinc (D) Manganese
Ans. (C)

56. Atomic number of an atom gives the number of
which of the following?
(A) Electrons (B) Protons
(C) Neutrons (D) Neutrons and protons
Ans. (B)

57. Atomic number of which of the following
elements is greater than that of Fluorine?
(A) Sodium (B) Beryllium
(C) Nitrogen (D) Boron
Ans. (A)

58. Atomic number of which of the following
elements is greater than that of Iron?
(A) Manganese (B) Cobalt
(C) Calcium (D) Chromium
Ans. (B)

59. Mass number is the sum of –
(A) Electrons and Protons
(B) Protons and Neutrons
(C) Electrons and Neutrons
(D) Only Protons
Ans. (B)

60. The mass number of an atom is–
(A) Always less than its atomic number
(B) Always more than its atomic number
(C) Always equal to its atomic number
(D) Sometimes more and sometimes equal to its atomic number
Ans. (D)

61. An Element has Atomic number 17 and Mass
number 36, then number of neutrons present in it–
(A) 17 (B) 19 (C) 36 (D) 53
Ans. (B)

62. Which of the following element has a relative atomic weight that is made up to atoms containing each of 17 protons, 18 Neutrons and 17 Electrons?
(A) 52 (B) 35 (C) 18 (D) 17
Ans. (B)

63. How many neutrons are there in 92U238 atoms?
(A) 92 (B) 238 (C) 146 (D) 330
Ans. (C)

64. The number of neutrons present in an element
having mass number 226 and atomic number 88 is:
(A) 88 (B) 138 (C) 314 (D) 50
Ans. (B)

65. Atomic mass of Oxygen is 16 and the atomic number is 8. What is the mass in grams of 2
moles of oxygen gas?
(A) 8 (B) 64 (C) 32 (D) 16
Ans. (B)

66. The photoelectric effect is described as the ejection of electrons from the surface of a metal when—
(A) It is heated
(B) It is placed in strong electric field
(C) Electrons of suitable velocity impings on it
(D) Light of suitable frequency falls on it
Ans. (D)

67. The photoelectric emission from metal surface
starts only when the incident light has a
certain minimum
(A) Wavelength (B) Velocity
(C) Frequency (D) Acceleration
Ans. (C)

68. Propagation of light quanta may be described by–
(A) Photons (B) Protons
(C) Neutrons (D) Electrons
Ans. (A)

69. The value of planck’s constant is—
(A) 6.62×10–34 J (B) 6.62×10–34 J.s
(C) 6.62×10–34 erg.s (D) None of these
Ans. (B)

70. If an electron and a photon have the same wavelength, then they will have the same
(A) Velocity (B) Linear momentum
(C) Angular momentum(D) Energy
Ans. (B)

71. Which of the following article has the dual nature of particle and wave?
(A) Neutron (B) Electron
(C) Meson (D) Proton
Ans. (B)
y
72. The concept of dual nature of radiation was proposed by—
(A) Max planck (B) De-Broglie
(C) Heisenberg (D) Pauling
Ans. (B)

73. “The position and velocity of a small particle-like electron can not be simultaneously
determined.“This statement is—
(A) Heisenberg uncertainty principle
(B) Pauli’s exclusion principle
(C) Aufbau principle
(D) De-broglie wave nature of electron
Ans. (A)

74. Who discovered X-Ray?
(A) Wilhelm Roentgen (B) William Lee
(C) X Lollswick (D) I Thompson
Ans. (A)

75. By which one of the following, an old written
material which can not be read easily, can be read?
(A) – rays (B) X – rays
(C) IR – rays (D) Radio frequency waves
Ans. (B)

76. Which one of the following is the correct sequence of the wavelength of radiations?
(A) UV > Green > IR > Hard X – rays
(B) IR > Green > UV > Hard X – rays
(C) UV > Hard X – rays > IR > Green
(D) IR > Hard X – rays > Green > UV
Ans. (B)

77. Which of the following is not Electromagnetic in nature?
(A) Cathode rays (B) X – rays
(C) Gamma – rays (D) Infrared – rays
Ans. (A)

78. Wavelength of which of the following colours
of the visible spectrum of light are maximum
absorbed by green plants –
(A) Green and yellow (B) Red and blue
(C) Green and red (D) Blue and yellow
Ans. (B)

79. Which of the following is not true about X rays?
(A) Low power
(B) Travel with the speed of light
(C) Refracted
(D) Can affect photographic plates
Ans. (A)

80. The reverse effect of X-ray emission is
(A) Raman effect (B) Compton effect
(C) Zeeman effect (D) Photo-electric effect
Ans. (D)

81. Which of the following has the lowest frequency?
(A) Visible light (B) Gamma rays
(C) X-rays (D) Ultraviolet rays
Ans. (A)

82. All isotopes of the same element have —
(A) Different atomic numbers and different atomic mass
(B) Different atomic numbers and the same atomic mass
(C) The same atomic number but different atomic mass
(D) The same atomic number and the same atomic mass
Ans. (C)

83. Nuclides have same atomic number are called:
(A) Isotopes (B) Isobar
(C) Isotones (D) Isoelectrons
Ans. (A)

84. Atoms of same element having different mass numbers are called —
(A) Isobars (B) Isotopes
(C) Isotones (D) Isomers
Ans. (B)

85. Chemical properties of isotopes
(A) Must be Same (B) Must be Different
(C) Need not be Same (D) Need not be Different
Ans. (A)

86. Atoms having the same number of protons but different number of neutrons are called:
(A) Isotopes (B) Cations
(C) Higgs-boson (D) Anions
Ans. (A)

87. Atoms of different elements have
(A) Same atomic number and same electronic configuration
(B) Different atomic numbers and the same electronic configuration
(C) Different atomic numbers and different number of valence electrons
(D) Same number of electrons and neutrons
Ans. (C)

88. Atoms having the same no of neutron but different
no of electrons or protons are called–
(A) Isotopes (B) Isobars
(C) Isotones (D) Allotropes
Ans. (C)

90. Isobars have –
(A) Same mass numbers but different atomic numbers
(B) Different mass numbers but same atomic numbers
(C) Same mass and atomic numbers
(D) Different mass and atomic numbers
Ans. (A)

91. Who was the first to explain the hydrogen spectrum?
(A) Dalton (B) Neil Bohr
(C) Rutherford (D) J.J. Thomson
Ans. (B)

92. Bohr’s model can explain :
(A) Spectrum of hydrogen atom only
(B) Spectrum of any atom or ion having one electron only
(C) Spectrum of the hydrogen molecule
(D) Solar spectrum
Ans. (B)

93. The value of Bohr radius of a hydrogen atom is
(A) 0.529 × 10–7 cm (B) 0.529 × 10–8 cm
(C) 0.529 × 10–9 cm (D) 0.529 × 10–10 cm
Ans. (B)

94. If r is the radius of first orbit, the radius of nth
orbit of the hydrogen atom will be :
(A) rn2 (B) rn
(C) r/n (D) r2n2
Ans. (A)

95. When a metal is heated in a flame, the electrons
absorb energy and jump to higher energy state.
On coming back to the lower energy state, they
emit light, which we can observe in
(A) Raman spectra (B) Absorption spectra
(C) Emission spectra (D) Fluoroscence
Ans. (C)

96. Bohr’s concept of the orbit in an atom was contradicted by
(A) De-broglie relationship
(B) Uncertainty principle
(C) Plancks hypothesis (D) Hunds rule
Ans. (B)

97. The total energy of revolving electron in an atom
(A) Cannot be negative
(B) Can have any value above zero
(C) Can never be positive
(D) Will always be positive
Ans. (C)

98. The spectrum of helium is expected to be
similar to that of:
(A) H (B) Na
(C) He+ (D) Li+
Ans. (D)

99. When an electron drops from a higher energy
level to a low energy level then:
(A) Energy is absorbed
(B) Energy is emitted
(C) Atomic number increases
(D) Atomic number decreases
Ans. (B)

100. In Lyman series an electron jumps from higher energy level to
(A) K energy level (B) M energy level
(C) N energy level (D) L energy level
Ans. (A)

101. In which region of the electromagnetic spectrum
does the Lyman series of hydrogen atom lie?
(A) X-Ray (B) Ultraviolet Ray
(C) Visible (D) Infrared
Ans. (B)

102. The total number of orbitals in a principal shell are:
(A) n (B) n²
(C) 2n² (D) 3n²
Ans. (B)

103. The mercury and sodium street lamps light up because of–
(A) Atomic absorption (B) Electron absorption
(C) Atomic emission (D) Electron emission
Ans. (C)

104. The atomic orbital is—
(A) The Circular path of the electron
(B) Elliptically shaped orbit
(C) Three-dimensional field around nucleus
(D) The region in which there is maximum probability of finding an electron
Ans. (D)

105. Which of the following atoms has a
nonspherical outermost orbital.
(A) H (B) Li
(C) Be (D) B
Ans. (D)

106. Orientation of atomic orbital is controlled by –
(A) Principal Quantum number
(B) Magnetic Quantum number
(C) Electron spin quantum number
(D) Azimuthal Quantum number
Ans. (B)

107. Two electrons in an orbital are differentiated by which of the following?
(A) Magnetic quantum number
(B) Spin quantum number
(C) Principal quantum number
(D) Azimuthal quantum number
Ans. (B)

108. “All the four quantum numbers of two electrons
in an atom are not the same.” It is the law of —
(A) Hund’s rule
(B) Pauli’s exclusion principle
(C) Uncertainty Principle of Heisenberg
(D) Avogadro’s Law
Ans. (B)

109. When there are two electrons in the same orbital, they have:
(A) Same spin (B) Opposite spin
(C) Same or opposite spin
(D) No spin
Ans. (B)

110. Which orbital is dumb-bell shaped?
(A) s-orbital (B) p-orbital
(C) d-orbital (D) f-orbital
Ans. (B)

111. In an atom the order of filling up of the orbitals is governed by—
(A) Aufbau principle
(B) Heisenberg’s uncertainty principle
(C) Hund’s rule
(D) Pauli’s exclusion Principle
Ans. (A)

112. According to Aufbau principle, the correct order of energy of 3d, 4s and 4p orbitals is:
(A) 4p < 3d < 4s (B) 4s < 4p < 3d (C) 4s < 3d < 4p (D) 3d < 4s < 4p Ans. (C) 113. The statement that the electron occupies available orbital singly before pairing occurs is called (A) Einstein principle (B) Rutherford hypothesis (C) Pauli's exclusion principle (D) Hund's rule Ans. (D) 114. The nitrogen atom has unpaired electrons. This can be explained as due to: (A) Hund's rule (B) Aufbau Principle (C) Pauli's exclusion principle (D) Heisenberg’s uncertainty principle Ans. (A) 115. The number of neutrons in an atom of hydrogen is (A) One (B) Zero (C) Two (D) Three Ans. (B) 116. The subatomic particle that does not have any electric charge is a/an _____. (A) Electron (B) Proton (C) Neutron (D) All options are correct. Ans. (C) 117. How is an atomic mass number determined? (A) By total number of protons (B) By total number of neutrons (C) By adding a number of protons and neutrons (D) By total number of electrons Ans. (C) 118. What are the components of the nucleus of an atom? (A) Only Protons (B) Protons and Neutrons (C) Neutrons and Electrons (D) Only Neutrons Ans. (B) 119. What is the mass of one mole of a substance in grams is called? (A) Nuclear Mass (B) Atomic Mass (C) Mass No. (D) Molecular Mass Ans. (D) 120. Which among the following is a negatively charged ion? (A) Calcium ion (B) Zinc ion (C) Silver ion (D) Iodine ion Ans. (D) 121. Atomic Number is denoted by which alphabet? (A) A (B) N (C) Z (D) E Ans. (C) 122. How are 'Cations' formed? (A) Addition of electron(B) Removal of electron (C) Addition of proton (D) Removal of proton Ans. (B) 123. How are 'anions' formed? (A) Addition of electron(B) Removal of electron (C) Addition of proton (D) Removal of proton Ans. (A) 124. Which amongst the following is not a Cation? (A) Aluminium ion (B) Copper ion (C) Sulphate ion (D) Zinc ion Ans. (C) 125. What are isobars? (A) Elements with the same atomic number but different mass number (B) Elements with different atomic numbers but same mass number (C) Elements with different atomic numbers and different mass number (D) Elements with the same atomic number and same mass number Ans. (B) 126. Anions are formed by _____. (A) Losing of electrons (B) Gaining of electrons (C) Gaining of neutrons (D) Losing of neutrons Ans. (B) 127. Who discovered Proton? (A) Ernest Rutherford (B) Friedrich Miescher (C) Goldstein (D) Henry Cavendish Ans. (C)

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