NCERT Class 11 Chemistry Chapter 2 Structure Of Atom Multiple Choice Questions

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NCERT Solutions For Class 11 Chemistry Chapter 2 Structure Of Atom Multiple Choice Questions

Question 1. The ionization potential of a hydrogen atom is 13.6 eV. A hydrogen atom in the ground state is excited by monochromatic light of energy 12.1 eV. The spectral lines emitted by hydrogen according to Bohr’s theory will be.

  1. One
  2. Two
  3. Three
  4. Four

Answer: 3. Three

Question 2. The number of waves made by a Bohr electron in an orbit of maximum magnetic quantum number 3 is-

  1. 4
  2. 3
  3. 2
  4. 1

Answer: 1. 4

Question 3. In which of the following cases would the probability of finding an electron residing in a d -d-orbital be zero

  1. xz and yz -planes
  2. xy and yz -planes
  3. z -direction, yz and xz -plane
  4. xy and xz -planes

Answer: 1. xz and yz -planes

Question 4. An electron beam with a de Broglie wavelength of P A is accelerated till its wavelength is halved. By what factor will kinetic energy change

  1. 2
  2. 1/4
  3. 4
  4. none

Answer: 3. 1/4

Question 5. If the Aufbau rule is not followed then the percent change in total (n + l) value for unpaired electrons in 25Mn is-

  1. 60
  2. 50
  3. 40
  4. 30

Answer: 3. 40

Question 6. If the shortest wavelength of the IT -atom in the Lyman series is X, then the longest wavelength in the Paschen series of He+ is

  1. \(\frac{36 X}{5}\)
  2. \(\frac{36 X}{7}\)
  3. \(\frac{7 X}{36}\)
  4. \(\frac{6 X}{5}\)

Answer: 2. \(\frac{36 X}{7}\)

Question 7. The atomic numbers of elements X, Y, and Z are 19, 21, and 25 respectively. The number of electrons present in the ‘M’ shells of these elements follows the order —

  1. Z<Y<x
  2. X<y<Z
  3. Z>X>Y
  4. Y>Z>X

Answer: 1. Z<Y<x

Question 8. Hydrogen atoms are excited in the n = 4 state. In the spectrum of the emitted radiation, the number of lines in the ultraviolet and visible regions are respectively—

  1. 2:3
  2. 3:1
  3. 1:3
  4. 3:2

Answer: 4. 3:2

Question 9. Which orbital has only a positive value of wave function at all distances from the nucleus—

  1. 3d
  2. 2p
  3. 2s
  4. 1s

Answer: 4. 1s

Question 10. The number of photons of light having wave number ‘a’ in the 32 energy source is

  1. \(\frac{h c}{3 a}\)
  2. 3hca
  3. \(\frac{3}{h c a}\)
  4. \(\frac{3}{h c a}\)

Answer: 3. \(\frac{3}{h c a}\)

Question 11. The wavelength of the de Broglie wave of the electron in the sixth orbit of-atom is—( r0 = Bohr’s radius)

  1. πr0
  2. 12πr0
  3. 6πr0
  4. 24πr0

Answer: 2. 12πr0

Question 12. In an orbit, the velocity of an electron in the excited state of Hatom is 1.093 × 108 cm-1 The circumference of this orbit is 

  1. 13.3Å
  2. 6.65Å
  3. 3.33Å
  4. 26.65Å

Answer: 1. 13.3Å

Question 13. Which have the largest number of unpaired electrons in p -p-orbitals in their ground state electronic configurations—

  1. Te, I, Xe
  2. F, Cl, Br
  3. Ne, Ar, K
  4. N, P, As

Answer: 4. N, P, As

Question 14. Which orbitals have two nodal planes passing through the nucleus —

  1. d
  2. p
  3. s
  4. None

Answer: 1. d

Question 15. Compared to the mass of the lightest nuclei, the mass of an electron is only-

  1. 1/80
  2. 1/800
  3. 1/1800
  4. 1/2800

Answer: 3. 1/1800

Question 16. Among the following sets of quantum numbers, which one Is Incorrect for 4d -electrons-

  1. \(4,3,2,+\frac{1}{2}\)
  2. \(4,3,2,+\frac{1}{2}\)
  3. \(4,2,-2, \frac{1}{2}\)
  4. \(4,2,1, \frac{-1}{2}\)

Answer: 2. \(4,3,2,+\frac{1}{2}\)

Question 17. Which d -orbitals have a different shape from the rest of all d orbitals—

  1. \(d_{x^2-y}\)
  2. dx
  3. dz²
  4. dyz

Answer: 3. dz²

Question 18. Which element possesses non-spherical shells

  1. He
  2. B
  3. Be
  4. Li

Answer: 2. B

Question 19. Which have the same number of s -electrons as the d electrons In Fe2+

  1. Li
  2. Na
  3. Na
  4. Fe

Answer: 4. Fe

Question 20. An anion X³ has 36 electrons and 45 neutrons. What is the mass number ofthe element X-

  1. 81
  2. 84
  3. 78
  4. 88

Answer: 3. 78

Question 21. Consider the set of quantum numbers \(3,2,-2,+\frac{1}{2}\), if the given subshell is filled. The next electron will enter the orbital with n and l value

  1. n = 3, l  = 3
  2. n = 4, l = 1
  3. n =1,l = 1
  4. n = 2, l-1

Answer: 2. n=4,l=1

Question 22. Given that an orbital is symmetric about the nucleus, then the value of azimuthal quantum number and magnetic quantum number are respectively

  1. -1+1
  2. +1+1
  3. 0,0
  4. 1,0

Answer: 3. 0,0

Question 23. A certain F.M. station broadcasts at a wavelength equal to 3.5 m. How many photons per second correspond to the transmission of one kilowatt–

  1. 2.24×1027
  2. 1.76×1028
  3. 2.26×1028
  4. 1.43×1026

Answer: 2. 1.7 6 ×1028

Question 24. A Bohr orbit in H-atom has a radius of 8.464 A. How many transitions may occur from this orbit to the ground state-

  1. 10
  2. 3
  3. 6
  4. 15

Answer: 3. 6

Question 25. The angular momentum of the electron in the 4/-orbital of a one-electron species according to wave mechanics is —

  1. \(\sqrt{3} \frac{h}{\pi}\)
  2. \(2 \frac{h}{\pi}\)
  3. \(\sqrt{\frac{3}{2}} \frac{h}{\pi}\)
  4. \(\sqrt{\frac{1}{2}} \frac{h}{\pi}\)

Answer: 1. \(\sqrt{3} \frac{h}{\pi}\)

Question 26. Consider the Structure of the ground Atom Mato of cnCr atom (z= 24).-The1 number of electrons with the azimuthal quantum numbers, =1 and 2 nrc respectively

  1. 12 and 4
  2. 12 and 5
  3. 16 and 4
  4. 16 and 5

Answer: 2. 12 and 5

Question 27. The magnetic moment of Mx+ (atomic number of M = 25 ) is Jl5 BM. The number of unpaired electrons and the value of x respectively are—

  1. 5,2
  2. 3,2
  3. 3,4
  4. 4,3

Answer: 3. 3,4

Question 28. Radial part of the wave function depends upon quantum numbers

  1. n and s
  2. 1 and m
  3. 1 and s
  4. n and 1

Answer: 1. n and s

Question 29. Which ofthe following pairs of nuclides are in diapers

  1. \({ }_6^{13} \mathrm{C} \text { and }{ }_8^{16} \mathrm{O}\)
  2. \({ }_6^{13} \mathrm{C} \text { and }{ }_8^{16} \mathrm{O}\)
  3. \({ }_1^3 \mathrm{H} \text { and }{ }_2^4 \mathrm{He}\)
  4. \({ }_{25}^{55} \mathrm{Mn} \text { and }{ }_{30}^{65} \mathrm{Zn}\)

Answer: 4. \({ }_{25}^{55} \mathrm{Mn} \text { and }{ }_{30}^{65} \mathrm{Zn}\)

Question 30. The dissociation energy of H2 is 430.53 kfrmol-1. If hydrogen is dissociated by illumination with radiation of wavelength 253.7 nm, the fraction of the radiant energy that will be converted into kinetic energy is given by

  1. 100%
  2. 8.76%
  3. 2.22%
  4. 1.22%

Answer: 2. 8.76%

Question 31. The correct order of penetrating power of 3s, 3p, and 3d electrons is

  1. 3d>3p>3s
  2. 3s>3p>3d
  3. 3s>3p>3d
  4. 3d>3s>3p

Answer: 3. 3s>3p>3d

Question 32. Hund’s rule pertains to the distribution of electrons in

  1. Principal energy shell
  2. An orbital
  3. Degenerate
  4. None of these

Answer: 3. Degenerate

Question 33. A principal shell having the highest energy subshell to be V can accommodate electrons to a maximum of—

  1. 18
  2. 32
  3. 25
  4. 50

Answer: 4. 50

Question 34. When an electron of H-atom jumps from a higher to lower energy, then—

  1. Its potential energy increases
  2. Its kinetic energy increases
  3. Its angular momentum remains unchanged
  4. Its de Broglie wavelength increases

Answer: 4. Its de Broglie wavelength increases

Question 35. What will be the number of spectral lines (AO observed if an electron undergoes a transition from n2 excited level to nl excited level in an atom of hydrogen—

  1. \(N=\frac{\left(n_2-n_1\right)\left(n_2-n_1+1\right)}{2}\)
  2. \(N=\frac{\left(n_1-n_2\right)\left(n_2-n_1+1\right)}{2}\)
  3. \(N=\frac{\left(n_2+n_1\right)\left(n_1+n_2+1\right)}{2}\)
  4. N = 2(nl-n2)(n2 + n1-l)

Answer: 1. \(N=\frac{\left(n_2-n_1\right)\left(n_2-n_1+1\right)}{2}\)

Question 36. The given diagram indicates the energy levels of certain atoms. When the system moves from 2E level to E, a photon of wavelength X is emitted. The wavelength of photon produced during its transition from level to E iS-

  1. \(\frac{\lambda}{3}\)
  2. \(\frac{3 \lambda}{3}\)
  3. \(\frac{4}{3} \lambda\)
  4. 3 λ

Answer: 4. 3 λ

Question 37. Electromagnetic radiation with maximum wavelength Is-

  1. Ultraviolet
  2. Radiowaves
  3. X-way
  4. infrared

Answer: 2. Radiowaves

Question 38. Brackett series are produced when the electrons from the outer orbits jump to—

  1. 2nd orbit
  2. 3rd orbit
  3. 4th orbit
  4. 5th orbit

Answer: 3. 4th orbit

Question 39. The following sets that do NOT contain isoelectronic species—

  1. \(\mathrm{BO}_3^{3-}, \mathrm{CO}_3^{2-}, \mathrm{NO}_3^{-}\)
  2. \(\mathrm{SO}_3^{2-}, \mathrm{CO}_3^{2-}, \mathrm{NO}_3^{-}\)
  3. \(\mathrm{CN}^{-}, \mathrm{N}_2, \mathrm{C}_2^{2-}\)
  4. \(\mathrm{PO}_4^{3-}, \mathrm{SO}_3^{2-}, \mathrm{ClO}_4^{-}\)

Answer: 2. \(\mathrm{SO}_3^{2-}, \mathrm{CO}_3^{2-}, \mathrm{NO}_3^{-}\)

Question 40. The hydrogen-like species Li2+ is in a spherically symmetric state S1 with one radial node. Upon absorbing light, the ion undergoes a transition to a state S2. The state S2 has one radial node and its energy is equal to the ground state energy ofthe hydrogen atom-

The state is

  1. 1s
  2. 2s
  3. 2p
  4. 3s

Answer: 2. 2s

 

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