Structure Of Atom Questions PDF

2.STRUCTURE OF ATOM 1. Choose the incorrect relation on the basis of Bohr’s theory 1 1 a) Velocity of electron ∝ 𝑛 b) Frequency of...

2.STRUCTURE OF ATOM 1. Choose the incorrect relation on the basis of Bohr’s theory 1 1 a) Velocity of electron ∝ 𝑛 b) Frequency of revolution ∝ 𝑛2 1 c) Radius of orbit ∝ 𝑛2 𝑍 d) Force on electron ∝ 𝑛4 2. X-rays were discovered by : a) Becquerel b) Roentgen c) Mme. Curie d) Van Laue 3. Two electrons in the same orbital may be identified with: a) 𝑛 b) 𝑙 c) 𝑚 d) 𝑠 4. An electron has principal quantum number 3. The number of its (i) subshells and (ii) orbitals would be respectively: a) 3 and 5 b) 3 and 7 c) 3 and 9 d) 2 and 5 5. Maximum number of electrons in a subshell of an atom is determined by the following: a) 2𝑛2 b) 4𝑙 + 2 c) 2𝑙 + 1 d) 4𝑙 − 2 6. Particle having mass 200 times that of an electron is: a) Proton b) Positron c) Meson d) Neutron 7. Which of the following has the maximum number of unpaired electrons? a) Mg 2+ b) Ti3+ c) Fe2+ d) V 3+ 8. An electron from one Bohr stationary orbit can go to next higher orbit a) By emission of electromagnetic radiation b) By absorption of any electromagnetic radiation c) By absorption of electromagnetic radiation of particular frequency d) Without emission or absorption of electromagnetic radiation 9. How many neutrons are present in tritium nucleus? a) 2 b) 3 c) 1 d) 0 10. The number of wave made by an electron moving in an orbit having maximum magnetic quantum number +3 is : a) 4 b) 3 c) 5 d) 6 11. The wavelength of a spectral line emitted by hydrogen atom in the Lyman series is 16 cm. What is the 15𝑅 value of 𝑛2 ?(𝑅=Rydberg constant) a) 2 b) 3 c) 4 d) 1 12. The statements, which is/are correct: a) Number of total nodes in an orbital = 𝑛 − 1 b) Number of radial nodes in an orbital = 𝑛 − 𝑙 − 1 c) Number of angular nodes in an orbital = 𝑙 d) All of the above 13. If the wavelength of an electromagnetic radiation is 2000Å, what is its energy in ergs? a) 9.94 × 10−12 b) 9.94 × 10−19 c) 4.97 × 10−12 d) 4.97 × 10−19 14. Number of unpaired electrons in the electronic configuration 1𝑠 2 , 2𝑠 2 2𝑝4 : a) 2 b) 3 c) 4 d) 6 15. A strong argument for the particle nature of cathode rays is that they: a) Produce fluorescence b) Travel through vacuum c) Get deflected by electric and magnetic fields d) Cast shadow 16. The electronic configuration 1𝑠 2 , 2𝑠 2 2𝑝6 , 3𝑠1 3𝑝1 correctly describes: a) Ground state of Na b) Ground state of Si+ c) Excited state of Mg d) Excited state of Al3+ 17. What accelerating potential is needed to produce an electron beam with an effective wavelength of  0.090Å? a) 1.86 × 104 eV b) 1.86 × 102 eV c) 2.86 × 104 eV d) 2.86 × 102 eV 18. Which of the following pairs have identical values of 𝑒/𝑚? a) A proton and a neutron b) A proton and deuterium c) Deuterium and an 𝛼-particles d) An electron and 𝛾-rays 19. Positive charge in an atom is: a) Scattered all over the atom b) Concentrated in the nucleus c) Revolving around the nucleus d) None is true 20. [Cr(H2 O)6 ]Cl3 (at. No. of Cr = 24) has a magnetic moment of 3.83 B. M. The correct distribution of 3𝑑 electrons in the chromium of the complex: 1 1 1 a) 3𝑑𝑥𝑦 , 3𝑑𝑦𝑧 , 3𝑑𝑥𝑧 1 b) 3𝑠𝑥𝑦 1 , 3𝑑𝑦𝑧 , 3𝑑𝑧12 c) (3𝑑𝑥1 2 −𝑦2 ) , 3𝑑𝑧12 , 3𝑑𝑥𝑧 1 d) 3𝑑𝑥𝑦 1 , (3𝑑𝑥1 2 −𝑦2 ) , 3𝑑𝑦𝑧 1 21. The mass of an electron is 𝑚, its charge is 𝑒 and it is accelerated from rest through a potential difference, 𝑉. The velocity of electron will be calculated by formula d) None of these 𝑉 𝑒𝑉 2𝑒𝑉 a) √ b) √ c) √( ) 𝑚 𝑚 𝑚 22. The present atomic weight scale is: a) C12 b) O16 c) H1 d) C13 23. Which one of the following set of quantum numbers is not possible for electron in the ground state of an atom with atomic number 19? a) 𝑛 = 2, 𝑙 = 0, 𝑚 = 0 b) 𝑛 = 2, 𝑙 = 1, 𝑚 = 0 c) 𝑛 = 3, 𝑙 = 1, 𝑚 = −1 d) 𝑛 = 3, 𝑙 = 2, 𝑚 = +2 24. Oxygen consists of O , O and O isotopes and carbon consists of isotopes of C12 and C13. Total number 16 17 18 of CO2 molecules possible are: a) 6 b) 12 c) 18 d) 1 25. In order to designate an orbital 𝑛 in an atom, the number of quantum number required are: a) 1 b) 2 c) 3 d) 4 26. For a given value of azimuthal quantum number 𝑙, the total number of values for the magnetic quantum number 𝑚 are given by: a) 𝑙 + 1 b) 2𝑙 + 1 c) 2𝑙 − 1 d) 𝑙 + 2 27. Magnetic quantum number for the last electron in sodium is: a) 3 b) 1 c) 2 d) Zero 28. The Heisenberg s uncertainty principle can be applied to: ′ a) A cricket ball b) A football c) A jet aeroplane d) An electron 29. Isotopes are a) Atoms of different elements having same mass number b) Atoms of same elements having same mass number c) Atoms of same elements having different mass number d) Atoms of different elements having same number of neutrons 30. Which element possess non-spherical shells? a) He b) B c) Be d) Li 31. Splitting of spherical lines when atoms are subjected to strong electric field is called: a) Zeeman effect b) Stark effect c) Decay d) Disintegration 32. An orbital in which 𝑛 = 4 and 𝑙 = 2 is expressed by a) 4𝑠 b) 4𝑝 c) 4𝑑 d) 5𝑝 33. Which wave property is directly proportional to energy of electromagnetic radiation:  a) Velocity b) Frequency c) Wave number d) All of these 34. Mass of an electron is : a) 9.1 × 10−28 g b) 9.1 × 10−25 g c) 9.1 × 10−10 g d) 9.1 × 10−18 g 35. Which is the correct outermost shell configuration of chromium? a) b) c) d) 36. Which of the following ion will show colour in aqueous solution? a) La3+ (𝑍 = 57) b) Ti3+ (𝑍 = 22) c) Lu3+ (𝑍 = 71) d) Sc 3+ (𝑍 = 21) 37. The electric configuration of element with atomic number 24 is a) 1𝑠 2 , 2𝑠 2 2𝑝6 , 3𝑠 2 3𝑝6 3𝑑4 , 4𝑠 2 b) 1𝑠 2 , 2𝑠 2 2𝑝6 , 3𝑠 2 3𝑝6 3𝑑10 c) 1𝑠 2 , 2𝑠 2 2𝑝6 , 3𝑠 2 3𝑝6 3𝑑6 d) 1𝑠 2 , 2𝑠 2 2𝑝6 , 3𝑠 2 3𝑝6 3𝑑5 , 4𝑠1 38. What is the maximum number of electrons in an atom that can have the following quantum numbers 𝑛 = 4, 𝑚1 = +1? a) 4 b) 15 c) 3 d) 6 39. The principal quantum number of an atom represents: a) Size and energy of the orbit b) Spin angular momentum c) Orbital angular momentum d) Space orientation of the orbitals 40. The specific charge for positive rays is much less than the specific charge for cathode rays. This is because: a) Positive rays are positively charged b) Charge on positive rays is less c) Positive rays comprise ionised atoms, whose mass is much higher d) Experimental method for determination is wrong 41. The magnetic moment of electron in an atom (excluding orbital magnetic moment) is given by: √𝑛(𝑛 + 2) Bohr d) None of the above a) b) √𝑛(𝑛 + 1)B. M. c) √𝑛(𝑛 + 3) B. M. Magneton (or B.M) 42. de Broglie equation is a relationship between: a) Position of an electron and its momentum b) Wavelength of an electron and its momentum c) Mass of an electron and its energy d) Wavelength of an electron and its frequency 43. Which electromagnetic radiation has extremely small wavelength? a) Radiowave b) Cosmic rays c) Infrared rays d) Microwaves 44. Dimensions of Planck’s constant are: a) force × time b) energy × distance c) energy/time d) energy × time 45. Given : The mass of electron is 9.11 × 10 kg and−31 Planck constant is 6.626 × 10−34 Js, the uncertainty involved in the measurement of velocity within a distance of 0.1 Å is: a) 5.79 × 108 m s−1 b) 5.79 × 105 m s−1 c) 5.79 × 106 m s−1 d) 5.79 × 107 m s−1 46. If helium atom and hydrogen molecules are moving with the same velocity, their wavelength ratio will be a) 4: 1 b) 1: 2 c) 2: 1 d) 1: 4 47. The energy required to break one mode of Cl − Cl bonds in Cl2 is 242kJmol. The longest wavelength of −1 light capable of breaking a single Cl − Cl bond is  a) 594 nm b) 640 nm c) 700 nm d) 494 nm 48. The uncertainty in momentum of an electron is 1 × 10 kg m/s. the uncertainty in its position will be −5 (ℎ = 6.62 × 10−34 kg m2 /s) a) 2.36× 10−28m b) 5.25× 10−28m c) 2.27× 10−30m d) 5.27× 10−30m 49. All types of electromagnetic radiations possess same: a) Energy b) Velocity c) Frequency d) Wavelength 50. The values of four quantum numbers of valence electron of an element are 1 𝑛 = 4, 𝑙 = 0, 𝑚 = 0 and𝑠 = + 2. The element is a) K b) Ti c) Na d) Sc 51. Ground state electronic configuration of nitrogen atom can be represented as a) b) c) d) 52. The value of charge on the oil droplets experimentally observed were −1.6 × 10−19 and −4 × 10−19 coulomb. The value of the electronic charge, indicated by these results is: a) 1.6 × 10−19 b) −2.4 × 10−19 c) −4 × 10−19 d) −0.8 × 10−19 53. Transition from 𝑛 = 4,5,6 to 𝑛 = 3 in hydrogen spectrum gives: a) Lyman series b) Paschen series c) Balmer series d) Pfund series 54. The atomic numbers of elements 𝑋, 𝑌 and 𝑍 are 19, 21 and 25 respectively. The number of electrons present in the 𝑀-shell of these elements follow the order a) 𝑍 > 𝑋 > 𝑌 b) 𝑋 > 𝑌 > 𝑍 c) 𝑍 > 𝑌 > 𝑋 d) 𝑌 > 𝑍 > 𝑋 55. The mass number of an element is 23 and atomic number is 11. The number of protons, electrons and neutrons respectively present in the atom of the elements are: a) 11, 11, 12 b) 12, 12, 11 c) 11, 12, 11 d) 12, 11, 12 56. In photoelectric emission the energy of the emitted electrons is: a) Larger than that of incident photon b) Smaller than that of incident photo c) Same as that of incident photon d) Proportional to intensity of incident light 57. Angular momentum of an electron in an orbital is given by : ℎ ℎ ℎ d) None of these a) 𝑛 b) × √𝑙(𝑙 + 1) c) 𝑛 2𝜋 2𝜋 4𝜋 58. What is the mass of a photon of sodium light with a wavelength of 5890 A° ?(ℎ = 6.63 × 10−27 erg-s) a) 5.685× 10−33 g b) 6.256 × 10−33 g c) 4.256× 10−33 g d) 3.752 × 10−33 g 59. Consider the ground state of (𝑍 = 24). The numbers of electrons with the azimuthal quantum numbers, 𝑙 = 1 and 2 are respectively a) 12 and 4 b) 12 and 5 c) 16 and 4 d) 16 and 5 60. The charge on an electron was discovered by a) J.J. Thomson b) Neil Bohr c) James Chadwick d) Mullikan 61. If an electron has spin quantum number of + 1 and a magnetic quantum number of −1, it cannot be 2 represented in an a) 𝑠 −orbital b) 𝑝 −orbital c) 𝑑 −orbital d) 𝑓 −orbital 62. The orbital angular momentum for an electron revolving in an orbit is given by √𝑙(𝑙 + 1) ℎ. This 2𝜋 momentum for an 𝑠-electron will be given by 1 ℎ b) Zero ℎ ℎ a) +. c) d) √2. 2 2π 2π 2π 63. A heavy element has atomic number 𝑋 and mass number 𝑌. Correct relationship between 𝑋 and 𝑌 is a) 𝑋 𝑌 b) 𝑋 𝑌 c) 𝑋 𝑌 d) 𝑋 𝑍 (1 𝑌)2 64. Proton is : a) Nucleus of deuterium  b) Ionised hydrogen molecule c) Ionised hydrogen atom d) An 𝛼-particle 65. An isotone of 76 32 Ge is a) 32 Ge 77 b) 77 33 As c) 77 34 Se d) 7836 Sc 66. Which principle/rule limits the maximum number of electrons in an orbital to two? a) Aufbau principle b) Pauli’s exclusion principle c) Hund’s rule of maximum multiplicity d) Heisenberg’s uncertainty principle 67. Magnitude of kinetic energy in an orbit is equal to a) Half of the potential energy b) Twice of the potential energy c) One fourth of the potential energy d) None of the above 68. The shortest 𝜆 for the Lyman series is: (Given 𝑅𝐻 = 109678 cm−1) a) 991 Å b) 700 Å c) 600 Å d) 811 Å 69. The maximum number of atomic orbitals associated with a principal quantum number 5 is: a) 9 b) 12 c) 16 d) 25 70. The number of orbitals present in the shell with 𝑛 = 4 is a) 16 b) 8 c) 18 d) 32 71. Which one of the following is the set of correct quantum numbers of an electron in 3𝑑 orbital? a) 𝑛 = 3, 𝑙 = 0, 𝑚 = 0, 𝑠 = −1/2 b) 𝑛 = 2, 𝑙 = 3, 𝑚 = 0, 𝑠 = +1/2 c) 𝑛 = 3, 𝑙 = 1, 𝑚 = 0, 𝑠 = −1/2 d) 𝑛 = 3, 𝑙 = 2, 𝑚 = 1, 𝑠 = +1/2 72. Different lines in Lyman series of hydrogen spectrum lie in …. region a) Ultraviolet b) Infrared c) Visible d) Far infrared 73. The first energy level that can have 𝑑-orbitals is: a) 2 b) 3 c) 4 d) All are correct 74. −5 −1 The uncertainty in the momentum of an electron is 1.0 × 10 kg ms. The uncertainty in its position will be a) 1.50 × 10−28 m b) 1.05 × 10−26 m c) 5.27 × 10−30 m d) 5.25 × 10−28 m 75. Which of the following particles moving with same velocity would be associated with smaller de-Broglie wavelength? a) Helium molecule b) Oxygen molecule c) Hydrogen molecule d) Carbon molecule 76. Stark effect refers to the a) Splitting up of the lines in an emission spectrum in the presence of an external electrostatic field b) Random scattering of light by colloidal particles c) Splitting up of the lines in an emission spectrum in a magnetic field d) Emission of electrons from metals when light falls upon them 77. For which species, Bohr′s theory does not apply: a) H b) Be c) He+ d) Li2+ 78. The energy of electron in first orbit of He+ is (𝑅H = −871.6 × 10−20 J). The energy of electron in the first orbit of H is: a) −871.6 × 10−20 J b) −435.8 × 10−20 J c) −217.9 × 10−20 J d) −108.9 × 10−20 J 79. The quantum levels upto 𝑛 = 3 has: a) 𝑠 and 𝑝-levels b) 𝑠, 𝑝, 𝑑, 𝑓-levels c) 𝑠, 𝑝, 𝑑-levels d) 𝑠-level 80. Which of the subshell has double dumb-bell shape? a) 𝑠 b) 𝑝 c) 𝑑 d) 𝑓 81. The lightest particle is a) -particle b) Positron c) Proton d) Neutron 82. The ratio of speed of 𝛾-rays and X-rays is: a) 1 b) < 1 c) > 1 d) None of these 83. The radius of second Bohr’s orbit of hydrogen atom is a) 0.053 nm b) 0.106 nm c) 0.2116 nm d) 0.4256 nm 84. Which set of phenomenon shown by the radiation proves the dual nature of radiation? a) Scintillation b) Interference and diffraction c) Interference and photoelectric effect d) None of the above 85. The hydrogen spectrum from an incandescent source of hydrogen is: a) A band spectrum in emission b) A line spectrum in emission c) A band spectrum in absorption d) A line spectrum in absorption 86. The total spin resulting from a 𝑑7 configuration is: a) ±1/2 b) ±2 c) ±1 d) ±3/2 87. The path of deflection of electron beam is: a) Directly proportional to the magnitude of applied magnetic field b) Inversely proportional to the magnitude of applied magnetic field c) Inversely proportional to the velocity of electron d) Directly proportional to the 𝑒/𝑚 value 88. Which one of the following groupings represents a collection of isoelectronic species? (At. no. Cs=55, Br=35) a) Na, Ca2 , Mg 2 b) N 3 , F, Na c) Be, Al3 , Cl d) Ca2 , Cs, Br 89. Which particle may be removed from a stable neutral atom with least energy change? a) An 𝛼-particle b) A neutron c) A proton d) An electron 90. Visible spectrum of hydrogen shows that it exists in two different forms which are based on direction of spin of the: a) Molecule of hydrogen b) Nuclei of hydrogen atoms c) Electrons of hydrogen d) Atoms of hydrogen molecule 91. Evidence for the existence of different energy levels in atom is supplied by: a) Spectral lines b) Mass defects c) Atomic numbers d) Atomic radii 92. Rutherford’s experiment on the scattering of α −particles showed for the first time that the atom has a) Electrons b) Protons c) Nucleus d) Neutrons 93. The longest 𝜆 for the Lyman series is : (Given 𝑅𝐻 = 109678 cm ) −1 a) 1215 Å b) 1315 Å c) 1415 Å d) 1515 Å 94. The angular momentum of electron in 𝑛th orbit is given by: ℎ 𝑛ℎ 𝑛2 ℎ a) 𝑛ℎ b) c) d) 2𝜋𝑛 2𝜋 2𝜋 95. According to Bohr′s postulates which quantity can take up only discrete values: a) Kinetic energy b) Angular momentum c) Momentum d) Potential energy 96. When the frequency of light incident on a metallic plate is doubled, the 𝐾𝐸 of the emitted photoelectrons will be: a) Doubled b) Halved c) Increased but more than doubled of the previous 𝐾𝐸 d) Unchanged 97. The mass of one mole of electron is: a) 0.55 mg b) 0.008 mg c) 1.008 mg d) 0.184 mg 98. The velocities of two particles 𝐴 and 𝐵 are 0.05 and 0.02ms−1 respectively. The mass of 𝐵 is five times the  mass of 𝐴. The ratio of their de-Broglie’s wavelength is a) 2: 1 b) 1: 4 c) 1: 1 d) l4: 1 99. Which are in the ascending order of wavelength? a) 𝐻𝛼 , 𝐻𝛽 , 𝐻𝛾 … lines in Balmer series of hydrogen atom b) Lyman limit, Balmer limit, Paschen limit in the hydrogen spectrum c) Blue, violet, yellow, red colours in solar spectrum d) None of the above 100. The representation of the ground state ↑ ↑ electronic configuration of He by box-diagram as is wrong because it violates a) Heisenberg’s uncertainty principle b) Bohr’s quantization theory of angular momenta c) Pauli exclusion principle d) Hund’s rule 101. The electronic configuration of the element which is just above the element with atomic number 43 in the same particle group is: a) 1𝑠 2 , 2𝑠 2 2𝑝6 , 3𝑠 2 3𝑝6 3𝑑10 , 4𝑠1 4𝑝6 b) 1𝑠 2 , 2𝑠 2 2𝑝6 , 3𝑠 2 3𝑝6 3𝑑5 , 4𝑠 2 c) 1𝑠 2 , 2𝑠 2 2𝑝6 , 3𝑠 2 3𝑝6 3𝑑6 , 4𝑠1 d) 1𝑠 2 , 2𝑠 2 2𝑝6 , 3𝑠 2 3𝑝6 3𝑑10 , 4𝑠 2 4𝑝5 102. The order of filling of electrons in the orbital of an atom will be: a) 3𝑑 4𝑠 4𝑝 4𝑑 5𝑠 b) 4𝑠 3𝑑 4𝑝 5𝑠 4𝑑 c) 5𝑠 4𝑝 3𝑑 4𝑑 5𝑠 d) 3𝑑 4𝑝 4𝑠 4𝑑 5𝑠 103. The Bohr′s energy equation for H atom reveals that the energy level of a shell is given by 𝐸 = −13.58/ 𝑛2 eV. The smallest amount that an H-atom will absorb, if in ground state is: a) 1.0 eV b) 3.39 eV c) 6.79 eV d) 10.19 eV 104. The amount of energy required to remove the electron from a Li ion in its ground state is how many 2+ times greater than the amount of energy required to remove the electron from an H atom in its ground state? a) 9 b) 2 c) 3 d) 5 105. Compared to mass of lightest nucleus the mass of an electron is only: a) 1/80 b) 1/360 c) 1/1800 d) 1/1000 106. Bragg’s equation will have no solution, if: a) 𝜆 > 2𝑑 b) 𝜆 < 2𝑑 c) 𝜆 < 𝑑 d) 𝜆 = 𝑑 107. Size of the nucleus is: a) 10−15 cm b) 10−13 cm c) 10−10 cm d) 10−8 cm 108. The radius of Bohr′s first orbit in H-atom is 0.053 nm. The radius of second orbit in He+ would be: a) 0.0265 nm b) 0.0530 nm c) 0.1060 nm d) 0.2120 nm 109. Splitting of spectrum lines in magnetic field is a) Stark effect b) Raman effect c) Zeeman effect d) Rutherford effect 110. If the radius of first Bohr′s orbit be 𝑎0 , then the radius of third Bohr′s orbit would be: a) 3 × 𝑎0 b) 6 × 𝑎0 c) 9 × 𝑎0 d) 1/9 × 𝑎0 111. Which of the following atoms has same number of protons and neutrons in its nucleus? a) Carbon b) Deuterium c) Tritium d) Nitrogen 112. The ratio of the difference in energy between the first and the second Bohr orbit to that between the second and the third Bohr orbit is 1 1 4 27 a) b) c) d) 2 3 9 5 113. The wavelength of radiation emitted when electron falls from 4th Bohr′s orbit to 2nd in H-atom is: (𝑅H = −1.09678 × 10−7 m−1) a) 972 nm b) 486 nm c) 243 nm d) 182 nm 114. In an atom with atomic number 29, mass number 59, the number of electrons is: a) 29 b) 30 c) 40 d) 59 115. The atomic transition gives rise to the radiation of frequency 10 MHz. The change in energy per mole of 4 atoms taking place would be a) 6.62 × 10−30 J b) 5.32 × 10−28 J c) 6.62 × 10−20 J d) 3.99 J 116. Uncertainty in the position of an electron (mass = 9.1 × 10 kg) moving with a velocity 300ms−1, −31 accurate upon 0.001% will be (ℎ = 6.63 × 10−34 Js) a) 19.2 × 10−2 m b) 5.76 × 10−2 m c) 1.92 × 10−2 m d) 3.84 × 10−2 m 117. Which of the following is not possible? a) 𝑛 = 2, 𝑙 = 1, 𝑚 = 0 b) 𝑛 = 2, 𝑙 = 0, 𝑚 = −1 c) 𝑛 = 3, 𝑙 = 0, 𝑚 = 0 d) 𝑛 = 3, 𝑙 = 1, 𝑚 = −1 118. The dynamic mass of a photon of wavelength 𝜆 is: a) Zero b) ℎ𝑐/𝜆 c) ℎ/𝑐𝜆 d) ℎ/𝜆 119. The atomic radius is of the order of : a) 10−8 cm b) 108 cm c) 10−10 cm d) 10−12 cm 120. When electronic transition occurs from higher energy state to a lower energy state with energy difference equal to ∆𝐸 expressed in electron volts, the wavelength of line emitted is approximately equal to: 12375 12375 12375 d) Either of these a) Å b) × 10−8 cm c) × 10−10 m ∆𝐸 ∆𝐸 ∆𝐸 121. A Mo atom in its ground state has a 4𝑑5 , 5𝑠1 configuration and a Ag atom 4𝑑10 , 5𝑠1 configuration. This is because a shell which is half-filled or completely filled is particularly a) Strongly exchange destabilized b) Weakly exchange stabilized c) Weakly exchange destabilized d) Strongly exchange destabilized 122. The ionisation enthalpy of hydrogen atom is 1.312 × 106 Jmol−1. The energy required to excite the electron in the atom from 𝑛1 = 1 to𝑛2 = 2 is a) 8.51 × 105 J mol−1 b) 6.56 × 105 J mol−1 c) 7.56 × 105 J mol−1 d) 9.84 × 105 J mol−1 123. Which of the following sets of quantum number is correct for an electron in 4𝑓-orbital? a) 𝑛 = 4, 𝑙 = 3, 𝑚 = +4, 𝑠 = +1/2 b) 𝑛 = 4, 𝑙 = 4, 𝑚 = −4, 𝑠 = −1/2 c) 𝑛 = 4, 𝑙 = 3, 𝑚 = +1, 𝑠 = +1/2 d) 𝑛 = 3, 𝑙 = 2, 𝑚 = −2, 𝑠 = +1/2 124. Number of electrons in −CONH2 are: a) 24 b) 20 c) 22 d) 18 125. The ratio of radii of two nuclei with mass numbers 27 and 64 is a) 1/2 b) 3/4 c) 3/2 d) 2/3 126. The atomic number of Ni and Cu are 28 and 29 respectively. The electronic configuration 1𝑠 2 2𝑠 2 2𝑝6 3𝑠 2 3𝑝6 3𝑑10 represents a) Cu+ b) Cu2+ c) Ni2+ d) Ni 127. The three quantum numbers 𝑛, 𝑙 and 𝑚 are the outcome of: a) Bohr’s atomic theory b) Solution of Schrödinger principle c) Heisenberg’s uncertainty principle d) Aufbau principle 128. Which has the highest 𝑒/𝑚 ratio? a) He2+ b) H + c) He+ d) D+ 129. The electronic configuration of an element in ultimate and penultimate orbitals is (𝑛 1)𝑠 2 (𝑛 1)𝑝6 (𝑛 1)𝑑 𝑥 𝑛𝑠 2. If 𝑛 4 and 𝑥 5 then number of protons in the nucleus is a) 25 b) 1 c) > 10 d) > 90 193. In photoelectric effect, the photo-current: a) Increases with increase of frequency of incident photon b) Decreases with increase of frequency of incident photon c) Does not depend on the frequency of photon but depends only on the intensity of incident light d) Depends both on intensity and frequency of the incident photon 194. Possible number of orientations of a subshell is: a) 𝑙 b) 𝑛 c) 2𝑙 + 1 d) 𝑛2 195. The orientation of an atomic orbital is governed by: a) Magnetic quantum number b) Principal quantum number c) Azimuthal quantum number d) Spin quantum number 196. The ratio of the radius of the orbit for the electron orbiting the hydrogen nucleus to that of an electron orbiting a deuterium nucleus is: a) 1 ∶ 1 b) 1 ∶ 2 c) 2 ∶ 1 d) 1 ∶ 3 197. Which of the following sets of quantum numbers is correct for an electron in 4𝑓-orbital? 1 a) 𝑛 = 3, 𝑙 = 2, 𝑚 = −2, 𝑠 = + 2 1 b) 𝑛 = 4, 𝑙 = 4, 𝑚 = −4, 𝑠 = − 2 1 c) 𝑛 = 4, 𝑙 = 3, 𝑚 = +1, 𝑠 = + 2 1 d) 𝑛 = 4, 𝑙 = 3, 𝑚 = +4, 𝑠 = + 2 198. The electronic energy levels of the hydrogen atom in the Bohr ′ s theory are called: a) Orbitals b) Orbits c) Rydberg levels d) Ground states 199. A photoelectric cell is a device, which : a) Converts light into electricity b) Converts electricity into light c) Stores lights d) Stores electricity 200. An 𝑓-shell containing 6 unpaired electrons can exchange a) 6 electrons b) 9 electrons c) 12 electrons d) 15 electrons 201. Mg is isoelectrionic with 2+ a) Cu2+ b) Zn2+ c) Na+ d) Ca2+ 202. The first orbital of H is represented by :  1 1 3/2 ψ= ( ) e−r/a0 , where a0 is Bohr′s radius. The probability of finding the electron at a distance 𝑟, √π a0 from the nucleus in the region 𝑑𝑉 is: a) ψ2 𝑑𝑟 b) ∫ ψ2 4π𝑟 2 𝑑v c) ψ2 4π𝑟 2 𝑑𝑟 d) ∫ ψ𝑑v 203. The correct statement about proton is a) It is a nucleus of deuterium b) It is an ionized hydrogen atom c) It is an ionized hydrogen molecules d) It is an 𝛼- particle 204. The energy ∆𝐸 corresponding to intense yellow line of sodium of 𝜆, 589 nm is: a) 2.10 eV b) 43.37 eV c) 47.12 eV d) 2.11 kcal 205. One electron volt is: a) 1.6 × 10−19 erg b) 1.6 × 10−12 erg c) 1.6 × 10−8 erg d) 1.6 × 108 erg 206. The quantum number that is in no way related to other quantum number is: a) 𝑙 b) 𝑠 c) 𝑛 d) 𝑚 207. The de-Broglie wavelength relates to applied voltage ror𝛼-particles as 12.3A° 0.286 ° 0.101 ° 0.856 ° a) 𝜆 = b) 𝜆 = A c) 𝜆 = A d) 𝜆 = A √𝑉 √𝑉 √𝑉 √𝑉 208. Calculate the wavelength (in nanometer) associated with a proton moving at 1.0 × 103 ms −1 (Mass of proton = 1.67 × 10−27 kg and ℎ = 6.63 × 10−34 Js) a) 0.032 nm b) 0.40 nm c) 2.5 nm d) 14.0 nm 209. The number of waves in an orbit are a) 𝑛2 b) 𝑛 c) 𝑛 – 1 d) 𝑛 – 2 210. Which of the following electron transition in hydrogen atom will require largest amount of energy? a) From 𝑛 = 1 to 𝑛 = 2 b) From 𝑛 = 2 to 𝑛 = 3 c) From 𝑛 = ∞ to 𝑛 = 1 d) From 𝑛 = 3 to 𝑛 = 5 211. The principal quantum number 𝑛 can have integral values ranging from: a) 0 to 10 b) 1 to ∞ c) 1 to (𝑛 = 𝑙) d) 1 to 50 212. Electrons will first enter into the set of quantum numbers 𝑛 = 5, 𝑙 = 0 or 𝑛 = 3, 𝑙 = 2 a) 𝑛 = 5, 𝑙 = 0 b) Both possible c) 𝑛 = 3, 𝑙 = 2 d) Data insufficient 213. The relationship between the energy 𝐸1 of the radiation with a wavelength 8000Å and the energy 𝐸2 of the radiation with a wavelength 16000Å is a) 𝐸1 = 6𝐸2 b) 𝐸1 = 2𝐸2 c) 𝐸1 = 4𝐸2 d) 𝐸1 = 1/2𝐸2 214. Which combinations of quantum numbers 𝑛, 𝑙, 𝑚 and 𝑠 for the electron in an atom does not provide a permissible solution of the wave equation? 1 1 1 1 a) 3, 2, 1, b) 3, 1, 1, − c) 3, 3, 1, − d) 3, 2, −2, 2 2 2 2 215. What is the lowest energy of the spectral line emitted by the hydrogen atom in the Lyman series? (ℎ=Planck’s constant, 𝑐=velocity of light, 𝑅=Rydberg’s constant). 5ℎ𝑐𝑅 4ℎ𝑐𝑅 3ℎ𝑐𝑅 7ℎ𝑐𝑅 a) b) c) d) 36 3 4 144 216. Which is not electromagnetic radiation? a) Infrared rays b) X-rays c) Cathode rays d) 𝛾-rays 217. Which one of the following sets of quantum numbers represents the highest energy level in an atom? 1 1 a) 𝑛 = 4, 𝑙 = 0, 𝑚 = 0, 𝑠 = + b) 𝑛 = 3, 𝑙 = 1, 𝑚 = 1, 𝑠 = + 2 2 1 1 c) 𝑛 = 3, 𝑙 = 2, 𝑚 = −2, 𝑠 = + d) 𝑛 = 3, 𝑙 = 0, 𝑚 = 0, 𝑠 = + 2 2 218. Which consists of particle of matter? a) Alpha rays b) Beta rays c) Cathode rays d) All of these 219. If 𝜆1 and 𝜆2 are the wavelength of characteristic X-rays and gamma rays respectively, then the relation between them is: a) 𝜆1 = 1/𝜆2 b) 𝜆1 = 𝜆2 c) 𝜆1 > 𝜆2 d) 𝜆1 < 𝜆2 220. Which best describe the emission spectra of atomic hydrogen? a) A series of only four lines b) A discrete series of lines of equal intensity and equally spaced with respect to wavelength c) Several discrete series of lines with both intensity and spacings between lines decreasing as the wave number increase within each series d) A continuous emission of radiation of all frequencies 221. In the ground state of the H-atom, the electron is : a) In the second shell b) In the nucleus c) Nearest to the nucleus d) Farthest from the nucleus 222. Atoms consist of electrons, protons and neutrons. If the mass attributed to neutron was halved and that attributed to the electrons was doubled, the atomic mass of 6 C12 would be approximately: a) Same b) Doubled c) Halved d) Reduced by 25% 223. The number of electrons in a neutral atom of an element is equal to its: a) Atomic weight b) Atomic number c) Equivalent weight d) Electron affinity 224. Which particle contains 2 neutrons and 1 proton? a) 1 H 2 b) 2 He4 c) 1 T 3 d) 1 D2 225. The highest number of unpaired electrons are in a) Fe b) Fe2+ c) Fe3+ d) All have equal number of unpaired electrons 226. Maximum number of electrons in an orbit is given by: a) 𝑛2 b) 2𝑛2 c) 𝑛2 /2 d) None of these 227. The wave nature of electron is verified by a) De-Broglie b) Davisson and Germer c) Rutherford d) All of these 228. Compared to the mass of lightest nuclei, the mass of an electron is only (app.) a) 1/80 b) 1/800 c) 1/1800 d) 1/2800 229. Which one of the following pair of atoms/atom-ion have identical ground state configuration? a) Li+ and He+ b) Cl− and Ar c) Na+ and K + d) F + and Ne 230. The total number of orbitals in a shell with principal quantum number ′𝑛′ is: a) 2𝑛 b) 2𝑛2 c) 𝑛2 d) 𝑛 + 1 231. Which of the following statements does not form a part of Bohr’s model of hydrogen atom? a) Energy of the electrons in the orbit is quantised 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 232. Penetration power of proton is: a) Greater than 𝑒 b) Less than electron c) Greater than ′𝑛′ d) None of these 233. Bohr’s theory is applicable to a) He b) Li2+ c) He2+ d) None of these 234. Which set of quantum numbers is possible for the last electron of Mg ion? + a) 𝑛 = 3, 𝑙 = 2, 𝑚 = 0, 𝑠 = +1/2 b) 𝑛 = 2, 𝑙 = 3, 𝑚 = 0, 𝑠 = +1/2 c) 𝑛 = 1, 𝑙 = 0, 𝑚 = 0, 𝑠 = +1/2 d) 𝑛 = 3, 𝑙 = 0, 𝑚 = 0, 𝑠 = +1/2 235. The electronic configuration for 26 Fe is: a) [Ar]3𝑑6 , 4𝑠 2 b) [Ar]3𝑑7 , 4𝑠 2 c) [Ar]3𝑑5 , 4𝑠 2 d) [Ar]3𝑑7 , 4𝑠1 236. Which of the following radial distribution graphs correspond to 𝑛 = 3, 𝑙 = 2 for an atom?  a) b) c) d) 237. In which orbital electron is most tightly bound to the nucleus? a) 5𝑠 b) 4𝑝 c) 4𝑑 d) 5𝑑 238. Ca is isoelectronic with 2 a) Na b) Ar c) Mg 2 d) Kr 239. Threshold wavelength depends upon : a) Frequency of incident radiation b) Velocity of electrons c) Work function d) None of the above 240. The electrons identified by quantum numbers I. 𝑛 = 4, 𝑙 = 1 II. 𝑛 = 4, 𝑙 = 0 III. 𝑛 = 3, 𝑙 = 2 IV. 𝑛 = 2, 𝑙 = 1 Can be placed in order of increasing energy from the lowest to highest as a) IV 𝐸2 b) 𝐸2 > 𝐸3 > 𝐸1 c) 𝐸1 > 𝐸2 > 𝐸3 d) 𝐸1 = 𝐸2 = 𝐸3 445. The frequency of first line of Balmer series in hydrogen atom is 𝑣0. The frequency of corresponding line emitted by singly ionised helium atom is : a) 2𝑣0 b) 4𝑣0 c) 𝑣0 /2 d) 𝑣0 /4 446. In a set of degenerate orbitals, the electrons distribute themselves to retain like spins as far as possible. This statement belongs to a) Pauli’s exclusion principle b) Aufbau principle c) Hund’s rule of maximum multiplicity d) Slater’s rule 447. Electrons occupy the available sub-level which has lower 𝑛 + 𝑙 value. This is called: a) Hund’s rule b) Aufbau principle c) Heisenberg’s uncertainty principle d) Pauli’s principle 448. Choose the correct statement among the following a) Ψ 2 represents the atomic orbital b) The number of peaks in radial distribution is 𝑛 − 𝑙 c) A node is a point in space around nucleus where the wave function Ψ has zero value d) All of the above 449. Which possesses an inert gas configuration? a) Fe3+ b) Cl− c) Mg + d) Cr 3+ 450. Angular momentum of an electron in the 𝑛th orbit of hydrogen atom is given by 𝑛ℎ 2𝜋 𝜋 a) b) 𝑛ℎ c) d) 2𝜋 𝑛ℎ 2𝑛ℎ 451. The discovered of neutron became very late because: a) Neutrons are present in nucleus b) Neutrons are fundamental particles c) Neutrons are chargeless d) All of the above 452. The frequency of a spectral line for electron transition in an atom is directly proportional to a) Number of electrons undergoing transition b) Velocity of electron c) The difference of energy between energy levels involved in the transition d) None of the above 453. Photoelectric emission is observed from a surface for frequency v1 and v2 of the incident radiation (v1 > v2 ). If the maximum kinetic energies of the photoelectrons in the two cases are in the ratio 1 ∶ 𝑘, then the threshold frequency v0 is given by: v2 − v1 kv − v2 kv − v1 v2 − v1 a) b) 1 c) 2 d) 𝑘−1 𝑘−1 𝑘−1 𝑘 454. The number of 2𝑝-electrons having spin quantum numbers 𝑠 = − 1/2 are a) 6 b) 0 c) 2 d) 3 455. Which statement relating to the spectrum of H atom is false? a) The lines can be defined by quantum number The lines of longest wavelength in the Balmerseries corresponds to the transition between 𝑛 = 3 and b) 𝑛 = 2 levels c) The spectral lines are closer together at longer wavelengths d) A continuum occurs at 𝑛 = ∞ 456. The atomic number of the element having maximum number of unpaired 3𝑝-electrons is:  a) 15 b) 10 c) 12 d) 8 457. The maximum wavelength of light that can excite an electron from first to third orbit of hydrogen atom is: a) 487 nm b) 170 nm c) 103 nm d) 17 nm 458. The incorrect statement about Bohr’s orbit of hydrogen atom is 2 ℎ2 b) KE of electron = PE of electron a) 𝑟 = 𝑛 𝑒 2 4𝜋 2 𝑚 (4𝜋𝜀 ) 0 2 𝑒2 2 d) None of the above is incorrect c) 1 2𝜋 𝑚 ( ) 4𝜋𝜀0 𝐸=− 2 𝑛 ℎ2 459. Four different sets of quantum numbers for 4 electrons are given below 1 1 𝑒1 = 4, 0, 0, − : 𝑒2 = 3, 1, 1, − 2 2 1 1 𝑒3 = 3, 2, 2, + : 𝑒4 = 3, 0, 0, + 2 2 The order of energy of 𝑒1 , 𝑒2 , 𝑒3 and 𝑒4 is a) 𝑒1 > 𝑒2 > 𝑒3 > 𝑒4 b) 𝑒4 > 𝑒3 > 𝑒2 > 𝑒1 c) 𝑒3 > 𝑒1 > 𝑒2 > 𝑒4 d) 𝑒2 > 𝑒3 > 𝑒4 > 𝑒1 460. When electrons in 𝑁-shell of excited hydrogen atom return to ground state, the number of possible lines spectrum is: a) 6 b) 4 c) 2 d) 3 461. The electrons occupying the same orbital have always spin: a) Paired b) Unpaired c) Both (a) and (b) d) None of these 462. The energy of hydrogen atom in its ground state is −13.6 eV. The energy of the level corresponding to the quantum number 𝑛=5 is a) −5.4 eV b) −0.54 eV c) −2.72 eV d) −0.85 eV 463. According to Bohr′s theory, the angular momentum for an electron of 5th orbit is: 2.5ℎ 5ℎ 25ℎ 6ℎ a) b) c) d) 𝜋 𝜋 𝜋 2𝜋 464. In which of the orbit of He , the angular momentum of the electron in ℎ/2𝜋? + a) First orbit b) Second orbit c) Third orbit d) Fourth orbit 465. Correct set of four quantum numbers for valence electron of rubidium (𝑍 = 37) is 1 1 1 1 a) 5,0,0, + 2 b) 5,1,0, + c) 5,1,1, + d) 6,0,0, + 2 2 2 466. Electron density in the YZ plane of 3𝑑𝑥 2 −𝑦2 orbital is a) Zero b) 0.50 c) 0.75 d) 0.90 467. The total number of orbitals possible for principle quantum number 𝑛 is a) 𝑛 b) 𝑛2 c) 2𝑛 d) 2𝑛2 468. Which does not characterise X-rays? a) The radiation can ionise gas b) It causes Zns to fluorescence c) Deflected by electric and magnetic fields d) Have wavelength shorter than ultraviolet rays 469. The velocity of an electron placed in 3rd orbit of H atom, will be a) 2.79 × 107 cm/s b) 9.27 × 1027 cm/s c) 7.29 × 107 cm/s d) 92.7 × 107 cm/s 470. The electronic configuration of an atom is 1𝑠 2 , 2𝑠 2 2𝑝3. The number of unpaired electrons in this atom is: a) 1 b) Zero c) 3 d) 5 471. The orbital angular momentum of an electron in 2𝑠 orbital is 1 ℎ b) Zero ℎ ℎ a) +. c) d) √2 2 2𝜋 2𝜋 2𝜋 472. In the atomic spectrum of hydrogen the series of lines observed in the visible region is: a) Balmer series b) Paschen series c) Bracket series d) Lyman series 473. According to Bohr’s model of hydrogen atom :  a) The linear velocity of the electron is quantised b) The angular velocity of the electron is quantised c) The linear momentum of the electron is quantised d) The angular momentum of the electron is quantised 474. Which transition of electron in the hydrogen atom emits maximum energy? a) 2 → 1 b) 1 → 4 c) 4 → 3 d) 3 → 2 475. The quantum number that does not describe the distance and the angular disposition of the electron: a) 𝑛 b) 𝑙 c) 𝑚 d) 𝑠 476. Li and Be are: 2+ 3+ a) Isotopes b) Isomers c) Isobars d) Isoelectronic 477. In H atom, the electron is de-excited from 5th shell to 1st shell. How many different lines may appear in line spectrum? a) 4 b) 8 c) 10 d) 12 478. The electronic configuration with maximum exchange energy will be 1 a) 3𝑑𝑥𝑦 1 3𝑑𝑦𝓏 1 3𝑑𝓏𝑥 4𝑠1 1 b) 3𝑑𝑥𝑦 1 3𝑑𝑦𝓏 1 3𝑑𝓏𝑥 3𝑑𝑥12 −𝑦2 3𝑑𝓏12 4𝑠1 2 c) 3𝑑𝑥𝑦 2 3𝑑𝑦𝓏 2 3𝑑𝓏𝑥 3𝑑𝑥22 −𝑦2 3𝑑𝓏12 4𝑠1 2 d) 3𝑑𝑥𝑦 2 3𝑑𝑦𝓏 2 3𝑑𝓏𝑥 2 2 3𝑑𝑥2 −𝑦2 3𝑑𝓏 2 4𝑠1 479. The orbital diagram in which aufbau principle is violated is: a) b) c) d) 480. In the ground state of Cu+, the number of shell occupied, sub-shells occupied, filliedorbitals and unpaired electrons respectively are a) 4,8,15,0 b) 3,6,15,1 c) 3,6,14,0 d) 4,7,14,2 481. If ℎ is Planck’s constant, the momentum of a photon of wavelength 0.01 Å is: a) 10−2 ℎ b) ℎ c) 102 ℎ d) 1012 ℎ 482. What does the electronic configuration 1𝑠 2 , 2𝑠 2 , 2𝑝5 , 3𝑠1 indicate? a) Ground state of fluorine b) Excited state of fluorine c) Excited state of neon d) Excited state of the O−2 ion 483. Each 𝑝-orbital and each 𝑑-orbital except one has lobes respectively as: a) 2,4 b) 1,4 c) 2,3 d) 1,1 484. Which of the following statements regarding an orbital is correct? a) An orbital is a definite trajectory around the nucleus in which electron can move b) An orbital always has spherical trajectory An orbital is the region around the nucleus where there is a 90 − 95% probability of finding all the c) electrons of an atom d) An orbital is characterized by 3 quantum numbers 𝑛, 𝑙 and 𝑚 485. An electronic transition in hydrogen atom results in the formation of Hα line of hydrogen in Lyman series, the energies associated with the electron in each of the orbits involved in the transition (in kcal mol−1) are a) −313.6, −34.84 b) −313.6, −78.4 c) −78.4, −34.84 d) −78.4, −19.6 486. The wavelengths of the radiations emitted when in a H atom, electron falls from infinity to stationary state 1, is: a) 9.1 × 10−8 nm b) 192 nm c) 406 nm d) 91 nm 487. The values of quantum numbers for the outermost electron in scandium (Sc = 21) are: a) 𝑛 = 3, 𝑙 = 2 b) 𝑛 = 3, 𝑙 = 3 c) 𝑛 = 4, 𝑙 = 0 d) 𝑛 = 2, 𝑙 = 3 488. Ultraviolet light of 6.2 eV falls on aluminium surface (work function = 4.2eV). The kinetic energy (in joule) of the fastest electron emitted is approximately:  a) 3 × 10−21 b) 3 × 10−19 c) 3 × 10−17 d) 3 × 10−15 489. The number of spherical nodes in 3𝑝 orbitals is a) 0 b) 1 c) 2 d) 3 490. The maximum number of electron in 𝑝-orbital with 𝑛 = 5, 𝑚 = 1 is a) 6 b) 2 c) 14 d) 10 491. The species that has same number of electrons as 16 S is:32 a) 16 S+ b) 17 Cl− c) 16 S− d) 17 Cl+ 492. Select the odd man: a) Deuteron b) Proton c) Electron d) Cyclotron 493. Assuming the velocity be same, which sub-atomic particle possesses smallest de Broglie wavelength; a) An electron b) A proton c) An 𝛼-particle d) All have same 𝜆 494. The chromium has different electronic configuration then what is expected according to aufbau principle because: a) Cr is a metal b) It belongs to 𝑑-block elments c) Half-filled 𝑑-orbitals give extra stability d) None of the above 495. If the ionisation potential for hydrogen atom is 13.6eV, then the wavelength of light required for the ionisation of hydrogen atom would be: a) 1911 nm b) 912 nm c) 68 nm d) 91.2 nm 496. Bohr′s atomic theory gave the idea of: a) Quantum numbers b) Shape of sub-levels c) Nucleus d) Stationary states 497. Which species has more electrons than protons? a) Cl− b) Ca2+ c) K + d) Sc 3+ 498. Electronic configuration of niobium (Nb = 41) is: a) [Kr]4𝑑4 , 5𝑠1 b) [Kr]4𝑑6 c) [Kr]4𝑑3 , 5𝑠 2 d) [Kr]5𝑠 2 5 𝑝3 499. The momentum of radiation of wavelength 0.33 nm is …kg m sec −1. a) 2 × 10−24 b) 2 × 10−12 c) 2 × 10−6 d) 2 × 10−48 500. Predict the total spin in Ni2+ ion: a) ±5/2 b) ±3/2 c) ±1/2 d) ±1 501. An increasing order (lowest first) for the values of 𝑒/𝑚 for electron (𝑒), proton (𝑝), neutron (𝑛) and alpha (𝛼) particle is: a) 𝑒, 𝑝, 𝑛, 𝛼 b) 𝑛, 𝛼, 𝑝, 𝑒 c) 𝑛, 𝑝, 𝑒, 𝛼 d) 𝑛, 𝑝, 𝛼, 𝑒 502. Choose the arrangement which shows the increasing value of 𝑒/𝑚 for 𝑒, 𝑝, 𝑛 and 𝛼-particles a) 𝑛 < 𝛼 < 𝑝 < 𝑒 b) 𝑒 < 𝑝 < 𝛼 < 𝑛 c) 𝑛 < 𝑝 < 𝑒 < 𝛼 d) 𝑝 < 𝑛 < 𝛼 < 𝑒 503. The ′𝑚′ value for an electron in an atom is equal to the number of 𝑚 value for 𝑙 = 1. The electron may be present in a) 3𝑑𝑥 2 −𝑦2 b) 5𝑓𝑥(𝑥 2 −𝑦2 ) c) 4𝑓𝑥3 /𝓏 d) None of these 504. The kinetic energy of an electron in the second Bohr′s orbit of a hydrogen atom is: (𝑎0 is Bohr′s radius) ℎ2 ℎ2 ℎ2 ℎ2 a) 2 2 b) c) d) 4𝜋 𝑚𝑎0 16𝜋 2 𝑚𝑎02 32𝜋 2 𝑚𝑎02 64𝜋 2 𝑚𝑎02 505. Number of electrons in nucleus of an element of atomic number 14 is: a) Zero b) 14 c) 7 d) 20 506. When an electron of charge 𝑒 and mass 𝑚 moves with velocity 𝑢 about the nuclear charge 𝑍𝑒 in the circular orbit of radius 𝑟, the potential energy of the electron is given by: a) 𝑍𝑒 2 /𝑟 b) −𝑍𝑒 2 /𝑟 c) 𝑍𝑒 2 /𝑟 2 d) 𝑚𝑢2 /𝑟 507. The orbital angular momentum of an electron revolving in a 𝑝-otbital is a) Zero ℎ ℎ 1 ℎ b) c) d) √2𝜋 2𝜋 2 2𝜋 508. The ratio of specific charge 𝑒/𝑚 of a proton to that of an 𝛼-particle is:  a) 1 ∶ 4 b) 1 ∶ 2 c) 1 ∶ 1/4 d) 1 ∶ 1/2 509. Possible values of ′𝑚′ for a given value of 𝑛 are: a) 𝑛2 b) 2𝑙 + 1 c) 𝑛 d) 2𝑙 510. Common name for proton and neutron is a) Deutron b) Positron c) Meson d) Nucleon 511. Two electrons 𝐴 and 𝐵 in an atom have the following set of quantum numbers: 𝐴: 3, 2, −2, +1/2, 𝐵: 3, 0, 0, +1/2, Which statement is correct for 𝐴 and 𝐵? a) 𝐴 and 𝐵 have same energy b) 𝐴 has more energy than 𝐵 c) 𝐵 has more energy than 𝐴 d) 𝐴 and 𝐵 represents same electron 512. Radius of nucleus is proportional to …where 𝐴 is mass number a) 𝐴 b) 𝐴1/3 c) 𝐴2 d) 𝐴2/3 513. The energy levels for 𝑧 𝐴(+𝑧−1) can be given by: a) 𝐸𝑛 for 𝐴(+𝑧−1) = 𝑍 2 × 𝐸𝑛 for H b) 𝐸𝑛 for 𝐴(+𝑧−1) = 𝑍 × 𝐸𝑛 for H 1 c) 𝐸𝑛 for 𝐴(+𝑧−1) = 𝑍2 × 𝐸𝑛 for H 1 d) 𝐸𝑛 for 𝐴(+𝑧−1) = 𝑍 × 𝐸𝑛 for H 514. The observation that the ground state of nitrogen atom has 3 unpaired electrons in its electronic configuration and not otherwise is associated with a) Pauli’s exclusion principle b) Hund’s rule of maximum multiplicity c) Heisenberg’s uncertainty relation d) Ritz combination principle 515. The energy of the electron in second Bohr′s orbit in the hydrogen atom is −3.41eV. The energy of the electron in second Bohr′s orbit of He+ ion would be: a) −85 eV b) −13.62 eV c) −1.70eV d) −6.82 eV 516. As an electron is brought from an infinite distance close to the nucleus of the atom, the energy of the electron-nucleus system: a) Increases to a greater positive value b) Decreases to a smaller positive value c) Decreases to a greater negative value d) Decreases to a smaller negative value 517. Beryllium’s fourth electron will have the four quantum numbers: 𝑛 𝑙 𝑚 𝑠 a) 1 0 0 + 1/2 b) 1 1 1 + 1/2 c) 2 0 0 + 1/2 d) 2 1 0 + 1/2 518. The electrons would go to lower energy levels first and then to higher energy levels according to which of the following? a) Aufbau principle b) Pauli′ s exclusion principle c) Hund′s rule of maximum multiplicity d) Heisenberg′s uncertainty principle 519. When the speed of electron increase, the specific charge: a) Decreases b) Increases c) Remains same d) None of these 520. In the absence of magnetic field 𝑝-orbitals are known as… fold degenerate a) Three b) Two c) One d) Four 521. In hydrogen spectrum least energetic transition of electrons are found in: a) Lyman series b) Balmer series c) Bracket series d) Pfund series 522. The electronic configuration of an element is 1𝑠 , 2𝑠 , 2𝑝 , 3𝑠 , 3𝑝 , 3𝑑 , 4𝑠. This represents its 2 2 6 2 6 5 2  a) Cationic form b) Anionic form c) Ground state d) Excited state 523. A body of mass 𝑥 kg is moving with a velocity of 100ms. Its de-Broglie wavelength is 6.62 × 10−35m. −1 Hence, 𝑥 is (ℎ = 6.62 × 10−34 Js) a) 0.1 kg b) 0.25 kg c) 0.15 kg d) 0.2 kg 524. Maximum number of electrons in a subshell with 𝑙 = 3 and 𝑛 = 4 is: a) 10 b) 12 c) 14 d) 16 525. One energy difference between the states 𝑛 = 2 and 𝑛 = 3 is 𝐸 eV, in hydrogen atom. The ionisation potential of H atom is: a) 3.2 𝐸 b) 5.6 𝐸 c) 7.2 𝐸 d) 13.2 𝐸 526. The first emission line in the electronic spectrum of hydrogen in the Balmer series appears at cm−1 9𝑅 7𝑅 3𝑅 −1 5𝑅 −1 a) cm−1 b) cm−1 c) cm d) cm 400 144 4 36 527. The probability of finding an electron residing in a 𝑝𝑥 orbital is not zero: a) In the 𝑦𝑧 plane b) In the 𝑥𝑦 plane c) In the 𝑦 direction d) In the 𝑧 direction 528. What is the electronic configuration of Mn ? 2+ a) [Ne]3𝑑5 , 4𝑠 0 b) [Ar]3𝑑5 , 4𝑠 2 c) [Ar]3𝑑5 , 4𝑠 0 d) [Ne]3𝑠 5 , 4𝑠 2 529. Number of neutron in C12 is a) 6 b) 7 c) 8 d) 9 530. Which of the following reaction led to the discovery of neutrons? a) 6 C16 + 1 𝑝1 → 7N 14 + 0 𝑛1 b) 4 Be9 + 2 He4 → 6C 12 + 0 𝑛1 c) 5 B11 + 1 D2 → 6C 11 + 0 𝑛1 d) 4 Be8 + 2 He4 → 11 6C + 0𝑛 1 531. Combination of an 𝛼-particle with a nuclide results in the formation of a new nuclide which has: a) Less number of neutrons b) Equal number of electrons c) Lower mass number d) Higher atomic number 532. The radius of which of the following orbit is same as that of the first Bohr’s orbit of hydrogen atom? a) Li2+ (𝑛 = 2) b) Li2+ (𝑛 = 3) c) Be3+ (𝑛 = 2) d) He+ (𝑛 = 2) 533. Which statement is not correct in case of isotopes of chlorine 17 Cl35 and 17 Cl37? a) Both have same atomic number b) Both have the same number of electrons c) Both have same number of neutrons d) Both have same number of protons 534. Which has minimum number of unpaired 𝑑-electrons? a) Fe3+ b) Co3+ c) Co2+ d) Mn2+ 535. The total spin for atoms with atomic number 7,24,34 and 36 will be a) 0,±1, ±3, ±3/2 b) ±1,0, ±3/2, ±3 c) ±3/2, ±3, ±1,0 d) ±3, ±1,0, ±3/2 536. A photo-sensitive metal is not emitting photo-electrons when irradiated. It will do so when threshold is crossed. To cross the threshold we need to increase : a) Intensity b) Frequency c) Wavelength d) None of these 537. The 𝐾𝐸 of electron in He will be maximum in: + a) 3rd orbit b) 2nd orbit c) 1st orbit d) In orbit with 𝑛 = ∞ 538. Which neutral atom has 18 electrons in its outer shell? a) Cu+ b) Pd c) Mn4+ d) Zn 539. Rutherford scattering formula fails for very small scattering angles because a) The kinetic energy of 𝛼- particles is larger b) The gold foil is very thin  c) The full nuclear charge of the target atom is partially screened by its electron d) All of the above 540. 3 𝑝-orbital has: a) Two non-spherical nodes b) Two spherical nodes c) One spherical and one non-spherical node d) One spherical and two non-spherical nodes 541. Rutherford’s alpha particle scattering experiment eventually led to the conclusion that: a) Mass and energy are related b) Electrons occupy space around the nucleus c) Neutrons are buried deep into the nucleus d) The point of impact with matter can be precisely determined 542. The 𝑑-orbital with the orientation along 𝑋 and 𝑌 axes is called: a) 𝑑𝑧2 b) 𝑑𝑧𝑥 c) 𝑑𝑦𝑧 d) 𝑑𝑥 2 −𝑦2 543. Which of the following transitions are not allowed in the normal electronic emission spectrum of an atom? a) 2𝑠 ⟶ 1𝑠 b) 2𝑝 ⟶ 1𝑠 c) 3𝑑 ⟶ 4𝑝 d) 5𝑝 ⟶ 3𝑠 544. In an atom two electrons move around the nucleus in circular orbits of radii 𝑅 and 4𝑅. The ratio of the time taken by them to complete one revolution is: a) 1 ∶ 4 b) 4 ∶ 1 c) 1 ∶ 8 d) 8 ∶ 7 545. The value of Planck’s constant is 6.63 × 10−34 Js. The velocity of light is 3.0 × 108 m s−1. Which value is closest to the wavelength in nanometre of a quantum of light with frequency of 8 × 1015 s −1 ? a) 2 × 10−25 b) 5 × 10−18 c) 4 × 10−8 d) 3 × 107 546. The number of electrons and protons in an atoms of third alkaline earth metal is a) 𝑒 20, 𝑝 20 b) 𝑒 18, 𝑝 20 c) 𝑒 18, 𝑝 18 d) 𝑒 19, 𝑝 20 547. In photoelectric effect the number of photo-electron emitted is proportional to : a) Intensity of incident beam b) Frequency of incident beam c) Velocity of incident beam d) Work function of photo cathode 548. Which of the following statements is wrong about cathode rays? a) They produce heating effect b) They carry negative charge c) They produce 𝑋 −rays when strike with material having high atomic masses d) None of the above 549. In an atom no two electrons can have the same value for all the quantum numbers. This was proposed by: a) Hund b) Pauli c) Dalton d) Avogadro 550. The minimum energy required to eject an electron from an atom is called : a) Kinetic energy b) Electrical energy c) Chemical energy d) Work function 551. The orbital angular momentum for an electron revolving in an orbit is √𝑙(𝑙 + 1). Thus momentum for a ℎ 2𝜋 𝑠-electron is: ℎ ℎ 1 ℎ d) Zero a) b) √2 ∙ c) ∙ 2𝜋 2𝜋 2 2𝜋 552. The binding energy of the electron in the lowest orbit of the hydrogen atom is 13.6 eV. The energies required in eV to remove an electron from three lowest orbits of the hydrogen atom are: a) 13.6, 6.8, 8.4 eV b) 13.6, 10.2, 3.4 eV c) 13.6, 27.2, 40.8 eV d) 13.6, 3.4, 1.5 eV 553. The probability of finding the electron in the orbital is a) 100% b) 90-95% c) 70-80% d) 50-60% 554. The correct de Broglie relationship is: 𝜆 ℎ ℎ 𝑢 a) =𝑝 b) 𝜆 = c) 𝜆 = d) 𝜆𝑚 = 𝑚𝑢 𝑚𝑢 𝑚𝑝 𝑝 555. The one electron species having ionisation energy of 54.4 eV is a) H b) He+ c) B 4+ d) Li2+ 556. The correct set of quantum numbers (𝑛, 𝑙 and 𝑚 respectively) for the unpaired electron of chlorine atom is a) 2, 1, 0 b) 2, 1, 1 c) 3, 1, 1 d) 3, 2, 1 557. If ′𝑅𝐻 ′ is the Rydberg constant, then the energy of an electron in the ground state of hydrogen atom is: 𝑅 𝑐 𝐼 ℎ𝑐 a) 𝐻 b) c) d) −𝑅𝐻 ℎ𝑐 ℎ 𝑅𝐻 𝑐ℎ 𝑅𝐻 558. The radius of hydrogen atom is 0.53Å. The radius of 3 Li2+ is of a) 1.27 Å b) 0.17 Å c) 0.57 Å d) 0.99 Å 559. Among the following series of transition metal ions, the one in which all metal ions have 3𝑑2 electronic configuration is (At. no. Ti=22, V=23, Cr=24, Mn=25) a) Ti3+ , V 2+ , Cr 3+ , Mn4+ b) Ti+ , V 4+ , Cr 6+ , Mn7+ c) Ti4+ , V 3+ , Cr 2+ , Mn3+ d) Ti2+ , V 3+ , Cr 4+ , Mn5+ 560. Total number of unpaired electrons, in an unexcited atom of atomic number 29 is: a) 1 b) 2 c) 3 d) 4 561. The work function for a metal is 4 eV. To emit a photoelectron of zero velocity from the surface of the metal, the wavelength of incident light should be: a) 2700 Å b) 1700 Å c) 5900 Å d) 3100 Å 562. The wave number of the first line in the Lyman series in hydrogen spectrum is a) 72755.5cm−1 b) 109678 cm−1 c) 82258.5 cm−1 d) 65473.6 cm−1 563. The nodes present in 3𝑝-orbitals are a) One spherical, one planar b) Two spherical c) Two planar d) One planar 564. Electronic configuration of deuterium atom is a) 1𝑠1 b) 2𝑠 2 c) 2𝑠1 d) 1𝑠 2 565. The number of 𝑑-electrons retained in Fe2+ (At. No. Fe=26) ions is a) 3 b) 4 c) 5 d) 6 566. For azimuthal quantum number 𝑙 = 3, the maximum number of electrons will be: a) 2 b) 6 c) Zero d) 14 567. Which of the following sets of quantum numbers is correct? 1 1 a) 𝑛 = 5, 𝑙 = 4, 𝑚 = 0, 𝑠 = + b) 𝑛 = 3, 𝑙 = 3, 𝑚 = +3, 𝑠 = + 2 2 1 c) 𝑛 = 6, 𝑙 = 0, 𝑚 + 1, 𝑠 = − d) 𝑛 = 4, 𝑙 = 2, 𝑚 = +2, 𝑠 = 0 2 568. Correct energy value order is a) 𝑛𝑠, 𝑛𝑝, 𝑛𝑑, (𝑛 − 1)𝑓 b) 𝑛𝑠, 𝑛𝑝, (𝑛 − 1)𝑑, (𝑛 − 2)𝑓 c) 𝑛𝑠, 𝑛𝑝, (𝑛 − 1)𝑑, (𝑛 − 1)𝑓 d) 𝑛𝑠, (𝑛 − 1)𝑑, 𝑛𝑝, (𝑛 − 1)𝑓 569. Which hydrogen like species will have same radius as that of Bohr orbit hydrogen atom? a) 𝑛 = 2, Li2+ b) 𝑛 = 2, Be3+ c) 𝑛 = 2, He+ d) 𝑛 = 3, Li2+ 570. The nucleus and an atom can be assumed to be spherical. The radius of the nucleus of mass no. 𝐴 is given by 1.25 × 10−13 × 𝐴1/3 cm.The atomic radius of atom is 1 Å. If the mass no. is 64, the fraction of the atomic volume that is occupied by nucleus is: a) 1.0 × 10−3 b) 5.0 × 10−5 c) 2.5 × 10−2 d) 1.25 × 10−13 571. The expression 𝑍𝑒 gives : a) The charge of 𝛼-particle b) The charge on an atom c) The charge on the nucleus of atomic number 𝑍 d) The kinetic energy of an 𝛼-particle 572. Which has the highest number of unpaired electrons? a) Mn b) Mn5+ c) Mn3+ d) Mn4+ 573. The ratio between the neutrons present in carbon and silicon with respect to atomic masses of 12 and 28 is:  a) 3 ∶ 7 b) 7 ∶ 3 c) 3 ∶ 4 d) 6 ∶ 28 574. The last electron placed in the third (𝑛 = 3) quantum shell for: a) Kr b) Zn c) Cu d) Ca 575. Which have the same number of 𝑠-electrons as the 𝑑-electrons in Fe ? 2+ a) Li b) Na c) N d) P 576. The number of spectral lines that can be possible when electrons in 7th shell in different hydrogen atoms return to the 2nd shell, is a) 12 b) 15 c) 14 d) 10 577. The value of Rydberg constant is a) 10,9678 cm−1 b) 10,9876 cm−1 c) 10,8769 cm−1 d) 10,8976 cm−1 578. In absence of Pauli exclusion principle, the electronic configuration of Li in ground state may be: a) 1𝑠 2 , 2𝑠 2 b) 1𝑠 3 c) 1𝑠1 , 2𝑠 2 d) 1𝑠 2 , 2𝑠1 2𝑝1 579. Which relates to light only as stream of particles? a) Diffraction b) Photoelectronic effect c) Interference d) Planck’s theory 580. Who introduced the concept of electron spin? a) Schrödinger b) Planck c) Bohr d) Uhlenbeck and Gaudsmit 581. The unit of wavelength (nm) is equal to: a) 10Å b) 100Å c) 1000Å d) 55Å 582. Mass of neutron is … times the mass of electron a) 1840 b) 1480 c) 2000 d) None of these 583. The highest excited state that unexcited hydrogen atom can reach when they are bombarded with 12.2 eV electron is: a) 𝑛 = 1 b) 𝑛 = 2 c) 𝑛 = 3 d) 𝑛 = 4 584. The total number of atomic orbitals in fourth energy level of an atom is: a) 4 b) 8 c) 16 d) 32 585. The radius of the first Bohr orbit of hydrogen atom is 0.529Å. The radius of the third orbit of H + will be a) 8.46 Å b) 0.705 Å c) 1.59 Å d) 4.79 Å 586. Particles, which can be added to the nucleus of an atom without changing the chemical properties, are called: a) Electrons b) Protons c) Neutrons d) 𝛼-particles 587. An electron with values 4, 3, −2 and + 1 for the set of four quantum numbers 𝑛, 𝑙, 𝑚1 and𝑚𝑠 , respectively, 2 belongs to a) 4𝑠 orbital b) 4𝑝 orbital c) 4𝑑 orbital d) 4𝑓 orbital 588. The total number of electrons that can be accommodated in all the orbitals having principal quantum number 2 and azimuthal quantum number 1 is: a) 2 b) 4 c) 6 d) 8 589. When atoms are bombarded with 𝛼-particles suffer deflections while others pass through undeflected. This is because : a) The force of attraction on the 𝛼-particle by the oppositely charged electrons is not sufficient b) The nucleus occupies much smaller volume compared to the volume of the atom c) The force of repulsion on the fast moving 𝛼-particle small d) The effect in the nucleus do not have any effect on the 𝛼-particles 590. How many electrons with 𝑙 = 3 are there in an atom having atomic number 54? a) 3 b) 10 c) 14 d) None of these 591. Suppose a completely filled or half filled set of 𝑝 or 𝑑-orbitals is spherically symmetrical. Point out the species, which is spherical symmetrical? a) O b) C c) Cl− d) Fe 592. The number of electrons and neutrons of an element is 18 and 20 respectively. Its mass number is a) 2 b) 17 c) 37 d) 38 593. Which 𝑑-orbital has different shape from rest of all 𝑑-orbital? a) 𝑑𝑥 2 −𝑦2 b) 𝑑𝑧2 c) 𝑑𝑥 2 𝑦 d) 𝑑𝑥𝑧 594. Photoelectric effect is the phenomenon in which: a) Photons come out of a metal when it is hit by a beam of electrons b) Photons come out of the nucleus of an atom under the action of an electric field c) Electrons come out of a metal with a constant velocity which depends on the frequency and intensity of incident light wave d) Electrons come out of a metal with different velocities not greater than a certain value which depends only on the frequency of the incident light wave and not on its intensity 595. Total number of orientations of sublevel in 𝑛𝑡ℎ orbit is: a) 2𝑛 b) 2𝑙 + 1 c) 𝑛2 d) 2𝑛2 596. What is the minimum energy that photons must posses in order to produce photoelectric effect with platinum metal? The threshold frequency for platinum is 1.3× 1015 s−1 a) 3.6 × 10−13 erg b) 8.2× 10−13erg c) 8.2× 10−14erg d) 8.6× 10−12erg 597. For an electron in a hydrogen atom, the wave function Ψ is proportional to exp−𝑡/𝑎0 , where 𝑎0 is the Bohr’s radius. What is the ratio of the probability of finding the electron at the nucleus to the probability of finding it at 𝑎0 ? 1 d) Zero a) 𝑒 b) 𝑒 2 c) 2 𝑒 598. Millikan’s oil drop experiment is used to find: a) 𝑒/𝑚 ratio of electron b) Electronic charge c) Mass of an electron d) Velocity of an electron 599. The maximum number of unpaired electrons present in 4𝑓-energy level is: a) 5 b) 7 c) 10 d) 6 600. According to Bohr’s model of the hydrogen atom, the radius of a stationary orbit characterised by the principle quantum number 𝑛 is proportional to : a) 𝑛−1 b) 𝑛 c) 𝑛−2 d) 𝑛2 601. Which one of the following has unit positive charge and 1 u mass? a) Electron b) Neutron c) Proton d) None of these 602. The frequency of a green light is 6 × 10 Hz. Its wavelength is: 14 a) 500 nm b) 5 nm c) 50,000 nm d) None of these 603. Among the following sets of quantum numbers, which one is incorrect for 4𝑑 −electron? 1 1 1 1 a) 4, 3, 2, + b) 4, 2, 1, + c) 4, 2, −2, + d) 4, 2, 1, − 2 2 2 2 604. Nitrogen has the electronic configuration 1𝑠 2 , 2𝑠 2 2𝑝𝑥1 2𝑝𝑦1 2𝑝𝑧1 and not 1𝑠 2 , 2𝑠 2 2𝑝𝑥2 2𝑝𝑥1 2𝑝𝑧0. It was proposed by: a) Aufbau principle b) Pauli′s exclusion principle c) Hund′s rule d) Uncertainty principle 605. Which one of the following sets of ions represents a collection of isoelectronic species? a) K + , Cl− , Ca2+ , Sc 3+ b) Ba2+ , Sr 2+ , K + , S 2− c) N 3− , O2− , F − , S 2− d) Li+ , Na+ , Mg 2+ , Ca2+ 606. The 𝑒/𝑚 ratio is maximum for: a) D+ b) He+ c) H + d) He2+ 607. The principle, which gives a way to fill the electrons in the available energy level is: a) Hund′ s rule b) Pauli′s exclusion principle c) Aufbau principle  d) None of the above 608. The ground state electronic configuration of nitrogen atom can be represented as a) ⥮ ⥮ ↿ ⇂ ↿ b) ⥮ ⥮ ↿ ⇂ ⇂ c) ⥮ ⥮ ⇂ ⇂ ⇂ d) All of the above 609. The uncertainty in position of a minute particle of mass 25 g in space is 10−5 m. The uncertainty in its velocity (in m s−1 ) is: a) 2.1 × 10−34 b) 0.5 × 10−34 c) 2.1 × 10−28 d) 0.5 × 10−23 610. Out of first 100 elements, number of elements having electrons in 3𝑑-orbitals are: a) 80 b) 10 c) 100 d) 60 611. Number of electrons in 1.8 mL of H2 O are: a) 6.02 × 1023 b) 6.02 × 1024 c) 6.02 × 1022 d) 6.02 × 1025 612. The number of orbitals present in the shell with 𝑛 = 4 is a) 8 b) 16 c) 18 d) 32 613. Number of electrons in the outermost orbit of the element of atomic number 15 is: a) 7 b) 5 c) 3 d) 2 614. The angular momentum of electron of H-atom is proportional to: 1 1 a) 𝑟 2 b) c) √𝑟 d) 𝑟 √𝑟 615. The total number of electrons present in 1 mL Mg: (Given density of 12 Mg 24 = 1.2 g/mL) a) 0.6 N b) 6 N c) 2 N d) 3 N 616. Which set of quantum number represents the electron of the lowest energy? a) 𝑛 = 2, 𝑙 = 0, 𝑚 = 0, 𝑠 = −1/2 b) 𝑛 = 2, 𝑙 = 1, 𝑚 = 0, 𝑠 = +1/2 c) 𝑛 = 4, 𝑙 = 0, 𝑚 = 0, 𝑠 = +1/2 d) 𝑛 = 4, 𝑙 = 0, 𝑚 = 0, 𝑠 = −1/2 617. Electron behaves both as a particle and a wave. This was proposed by a) Heisenberg b) Gilbert N. Lewis c) de-Broglie d) L. Rutherford 618. Which of the following is isoelectronic with carbon atom? a) N + b) O2− c) Na+ d) Al3+ 619. The uncertainity in position for a dust particle (𝑚 = 10−11 g ; diameter = 10−4 cm and velocity = 10−4 cm/s) will be (The error in measurement of velocity is 1%) a) 5.27 × 10−4 cm b) 5.27 × 10−5 cm c) 5.27 × 10−6 cm d) 5.27 × 10−7 cm 620. Which is not basic postulate of Dalton’s atomic theory? a) Atoms are neither created nor destroyed in a chemical reaction b) In a given compound, the relative number and kinds of atoms are constant c) Atoms of all elements are alike, including their masses d) Each element is composed of extremely small particles called atoms 621. Among the various quantum numbers (𝑛, 𝑙, 𝑚, 𝑠) describing an electron, which can have the largest value: a) 𝑛 b) 𝑙 c) 𝑚 d) 𝑠 622. The valency orbital configuration of an element with 𝑍 = 23 is: a) 3𝑑5 b) 3𝑑3 , 4𝑠 2 c) 3𝑑2 , 4𝑠1 4 𝑝1 d) 3𝑑3 , 4𝑠1 4 𝑝1 623. A particle of mass, ′𝑚′ when annihilated completely given an energy 𝐸 equal to: a) 𝑚𝑐 2 b) 𝑚/𝑐 2 c) 𝑚𝑐 d) 𝑐 2 /𝑚 624. The correct set of four quantum number for the valence electron of rubidium (𝑍=37) is a) 𝑛 = 5, 𝑙 = 0, 𝑚 = 0, 𝑠 = +1/2 b) 𝑛 = 5, 𝑙 = 1, 𝑚 = 1, 𝑠 = +1/2 c) 𝑛 = 5, 𝑙 = 1, 𝑚 = 1, 𝑠 = +1/2 d) 𝑛 = 6, 𝑙 = 0, 𝑚 = 0, 𝑠 = +1/2 625. A photon is : a) A quanta of light (or electromagnetic) energy b) A quanta of matter  c) A positively charged particle d) An instrument for measuring light intensity 626. Which orbital is dumb-bell shaped? a) 𝑠 b) 2𝑝𝑦 c) 3𝑠 d) 3𝑑𝑧2 627. Aufbau principle does not give the correct arrangement of filling up of atomic orbital’s in a) Cu and Zn b) Co and Zn c) Mn and Cr d) Cu and Cr 628. Ordinary oxygen contains: a) Only O-16 isotope b) Only O-17 isotope c) A mixture of O-16 and O-18 isotopes d) A mixture of O-16,O-17 and O-18 isotopes 629. The approximate quantum number of a circular orbit of diameter, 20.6 nm of the hydrogen atom according to Bohr′s theory is: a) 10 b) 14 c) 12 d) 16 630. A 𝑝-orbital in a given shell can accommodate upto a) Four electrons b) Two electrons with parallel spin c) Six electrons d) Two electrons with opposite spin 631. An electron beam is accelerated through a potential difference of 10,000 volt. The de-Broglie wavelength of the electron beam is a) 0.123 A° b) 0.356 A° c) 0.186 A° d) 0.258 A° 632. Transition of electron from 𝑛 = 3 to 𝑛 = 1 level results in: a) X-ray spectrum b) Emission spectrum c) Band spectrum d) Infrared spectrum 633. Atomic radius is of the order of 10−8 cm and nuclear radius of the order of 10−13 cm. The fraction of atom occupied by nucleus is: a) 10−5 b) 105 c) 10−15 d) None of these 634. The ratio of the masses of proton and neutron are: a) > 1 b) < 1 c) = 1 d) > √1 635. If the mass number of an element is 𝑊 and its atomic number is 𝑁, then: a) Number of −1 𝑒 0 = 𝑊 − 𝑁 b) Number of protons ( 1 𝐻1 ) = 𝑊 − 𝑁 c) Number of 0 𝑛1 = 𝑊 − 𝑁 d) Number of 0 𝑛1 = 𝑁 636. For a particular value of azimuthal quantum number, the total number of magnetic quantum number values are given by 𝑚+1 𝑚−1 2𝑚 + 1 2𝑙 + 1 a) 𝑙 = b) 𝑙 = c) 𝑙 = d) 𝑚 = 2 2 2 2 637. The relation between energy of a radiation and its frequency was given by: a) De Broglie b) Einstein c) Planck d) Bohr 638. The filling of 4𝑝-sublevel starts in the element of atomic number: a) 29 b) 31 c) 35 d) 19 639. The angular speed of the electron in the 𝑛th orbit of Bohr hydrogen atom is : a) Directly proportional to 𝑛 b) Inversely proportional to √𝑛 c) Inversely proportional to 𝑛2 d) Inversely proportional to 𝑛3 640. The chlorine atom differs from chloride ion in the number of: a) Protons b) Neutrons c) Electrons d) None of these 641. If the ionisation potential for hydrogen atom is 13.6 eV, then the ionisation potential for He+ ion should be a) 13.6 eV b) 6.8 eV c) 54.4 eV d) 72.2 eV 642. The 𝜆 for 𝐻𝛼 line of Balmer series is 6500 Å. Thus, 𝜆 for 𝐻𝛽 line of Balmer series is :  a) 4814 Å b) 4914 Å c) 5014 Å d) 4714 Å 643. According to Bohr’s theory, the angular momentum for an electron of 3rd orbit is ℎ a) 3 ℎ b) 1.5 ℎ c) 9 ℎ d) 2 𝜋 644. The de-Broglie equation applies a) To protons only b) To electrons only c) All the material objects in motion d) To neutrons only 645. Which of the following electronic configuration is not possible? a) 1𝑠 2 , 2𝑠 2 b) 1𝑠 2 , 2𝑠 2 2𝑝6 c) [Ar]3𝑑10 , 4𝑠 2 4𝑝2 d) 1𝑠 2 , 2𝑠 2 2𝑝2 , 3𝑠1 646. Maximum number of electrons which can be accommodated in a 𝑔-subshell is: a) 14 b) 18 c) 12 d) 20 647. The correct ground state electronic configuration of chromium is a) [Ar]3𝑑5 4𝑠1 b) [Ar]3𝑑4 4𝑠 2 c) [Ar]3𝑑6 4𝑠 0 d) [Ar]4𝑑5 4𝑠1 648. The ionisation energy of hydrogen atom is 13.6 eV. What will be the ionisation energy of He+ ? a) 13.6 eV b) 54.4 eV c) 122.4 eV d) Zero 649. If each hydrogen atom is excited by giving 8.4 eV of energy, then the number of spectral lines emitted is equal to: a) None b) Two c) Three d) Four 650. ψ (psi) the wave function represents the probability of finding electron. Its value depends: 2 a) Inside the nucleus b) Far from the nucleus c) Near the nucleus d) Upon the type of orbital 651. The orbital angular momentum of an electron in a 𝑑-orbital is ℎ ℎ ℎ 2ℎ a) √6 b) √2 c) d) 2𝜋 2𝜋 2𝜋 2𝜋 652. The space between the proton and electron in hydrogen atom is: a) Filled with air b) Empty c) Filled with magnetic radiation d) None of the above 653. When 4𝑓-level of an atom is completely filled with electrons, the next electron will enter: a) 5𝑠 b) 6𝑠 c) 5𝑑 d) 5𝑝 654. The number of unpaired electrons in Fe ion is 3+ a) 3 b) 1 c) 5 d) 2 655. The number of 𝑑-electrons in Fe2+ (at. No. of Fe = 26) is not equal to that of the: a) 𝑝-electrons in Ne (at. no. = 10) b) 𝑠-electrons in Mg (at. no. = 12) c) 𝑑-electrons in Fe d) 𝑝-electrons in Cl− (at. no. Cl = 17) 656. When the value of azimuthal quantum number is 1, magnetic quantum number can have values : a) −1 only b) +1 only c) +1, 0, −1 d) +1 and −1 657. The H atom electron dropped from 𝑛 = 3 to 𝑛 = 2, then energy emitted is a) 1.9 eV b) 12 eV c) 10.2 eV d) 0.65 eV 658. The 𝑛 + 𝑙 value for the 3 𝑝-energy level is: a) 4 b) 7 c) 3 d) 1 659. The maximum number of sublevels, orbitals and electrons in 𝑁-shell of an atom are respectively a) 4, 12, 32 b) 4, 16, 30 c) 4, 16, 32 d) 4, 32, 64 660. A particle having a mass of 1.0 mg has a velocity of 3600 km/h. Calculate the wavelength of the particle (ℎ = 6.626 × 10−27 erg − s) a) 6.626 × 10−28 cm b) 6.626 × 10−29 cm c) 6.626 × 10−30 cm d) 6.626 × 10−31 cm 661. The target used for production of X-ray beam must have: a) High melting point and high atomic number b) High melting point and low atomic number c) Low melting point and low atomic number d) Low melting point and high atomic number 662. When photons of energy 4.25eV strike the surface of a metal 𝐴, the ejected photoelectrons have maximum kinetic energy, 𝑇𝐴 (expressed in eV) and de Broglie wavelength 𝜆𝐴. The maximum kinetic energy of photoelectrons liberated from another metal 𝐵 by photons of energy 4.70V is 𝑇𝐵 = 𝑇𝐴 − 1.50 eV. If the de Broglie wavelength of these photoelectrons is 𝜆𝐵 = 2𝜆𝐴 , then which is not correct? a) The work function of 𝐴 is 2.25 eV b) The work function of 𝐵 is 3.70 eV c) 𝑇𝐴 = 2.00eV d) 𝑇𝐵 = 0.5eV 663. An electrons is in one of the 3𝑑-orbitals, which of the quantum number is not possible? a) 𝑙 = 1 b) 𝑛 = 3 c) 𝑚 = 1 d) 𝑚 = 2 664. The momentum of a photon is 𝑝. The corresponding wavelength is: a) ℎ/𝑝 b) ℎ𝑝 c) 𝑝/ℎ d) ℎ/√𝑝 665. An electron, a proton and an alpha particle have KE of 16𝐸, 4𝐸 and 𝐸 respectively. What is the qualitative order of their de-Broglie wavelengths? a) 𝜆𝑒 > 𝜆𝑝 > 𝜆𝛼 b) 𝜆𝑝 = 𝜆𝛼 > 𝜆𝑒 c) 𝜆𝑝 < 𝜆𝑒 < 𝜆𝛼 d) 𝜆𝛼 < 𝜆𝑒 ≈ 𝜆𝑝 666. How many sets of four quantum number are possible for the electrons present in He2− ? a) 4 b) 3 c) 2 d) None of these 667. Which of the following has the maximum number of unpaired ‘𝑑’ electrons? a) Zn2+ b) Fe2+ c) Ni3+ d) Cu+ 668. The electrons, identified by quantum number 𝑛 and 𝑙, V. 𝑛 = 3; 𝑙 = 2 VI. 𝑛 = 5; 𝑙 = 0 VII. 𝑛 = 4; 𝑙 = 1 VIII. 𝑛 = 4; 𝑙 = 2 IX. 𝑛 = 4; 𝑙 = 0 can be placed in order of increasing energy, as a) I