UP Board Class 11 Chemistry Chapter 2 Structure Of Atom Multiple Choice Questions

UP Board Class 11 Chemistry Chapter 2 Structure Of Atom Multiple Choice Questions

Question 1. The energy of the state S1 in units of the hydrogen atom ground state energy is-

1. 0.75
2. 1.50
3. 2.25
4. 4.50

Answer: 3. 2.25

Question 2. In an atom, an electron is moving with a speed of 600 m/s with an accuracy of 0.005% certainty with which the position ofthe electron can be located is{h = 6.6 × 10^-34 kg-m² s^-1, the mass of the electron, mg = 9.1 × 10^-31 kg).

1. 3.84 × 10^-3m
2. 1.52 × 10^-4 m
3. 5.10 ×10^-3m
4. 1.92 × 10^-3m

Answer: 2. 1.52 ×10^-4m

Question 3. The ionization enthalpy of a hydrogen atom is 1.312 × 10⁶J-mol^-1 The energy required to excite the electron in the atom from n – 1 to n = 2 is

1. 7.56 × 10⁵ J-mol^-1
2. 9.84 × 10⁵ J-mol^-1
3. 8.51 × 10⁵ J-mol^-1
4. 6.56 × 10⁵ J-mol^-1

Answer: 2. 9.84 ×10⁵ J-mol^-1

Question 4. If we apply potential difference so that an electron is accelerated continuously in a vacuum tube such that a decrease of 10% occurs in its de-Broglie wavelength. In such a case the change observed in the kinetic energy of the election will be approximately—

1. A Decrease Of 11%
2. An increase of 11.1%
3. An Increase Of 10%
4. An increase of 23.4%

Answer: 4. An increase of 23.4%

Question 5. The approximate wavelength of matter wave associated with an electron, that is accelerated by applying 100 V of potential difference in a discharge tube, will be-

1. 123pm
2. 12.3pm
3. 1.23 pm
4. 0.123pm

Answer: 1. 123pm

Question 6. If two particles are associated with the same kinetic energy, then the de Broglie’s wavelength (A) of these particles are—

1. Directly proportional to the velocity
2. Inversely proportional to the velocity
3. Independent of mass and velocity
4. Cannot be predicted.

Answer: 1. Directly proportional to the velocity

Question 7. The ratio of magnetic moments of Fe (3) and CO (2) is

1. \(\sqrt{3}: \sqrt{7}\)
2. \(\sqrt{3}: \sqrt{7}\)
3. 7:3
4. 3:7

Answer: 2. \(\sqrt{3}: \sqrt{7}\)

Question 8. If it were possible for a hydrogen atom to exist with a position as the extra-nuclear particle, then the energy of position in the first excited state would be—

1. 13.6v
2. 3.4ev
3. -3.4ev
4. 6.8ev

Answer: 2. 3.4ev

Question 9. Identify the orbitals for which n = 4 and l = 1 

1. 4p_y
2. 4p_x
3. 4d_xy
4. 4d_x²-y²

Answer: 1. 4py

Question 10. The orbitals which have the same number of nodes are

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

Answer: 2. 3p,3d

Question 11. In the ground state, an element has 13 electrons in its Afshell. The element is

1. Mn
2. Cr
3. Ni
4. Fe

Answer: 1. Mn

Question 12. The angular momentum of an electron may have the values—

1. \(0.5 \frac{h}{\pi}\)
2. \(\frac{h}{\pi}\)
3. \(0.2 \frac{h}{\pi}\)
4. \(2.5 \frac{h}{2 \pi}\)

Answer: 1. \(0.5 \frac{h}{\pi}\)

Question 13. The line spectrum is noticed during the transition of an electron from a higher excited state to a lower one in the H-atom only when it falls from

1. 2s→ls
2. 2p→ls
3. 3s→2p
4. 4p→2p

Answer: 3. 3s→2p

Question 14. Select the pair of atoms having the same no. of electrons in their outermost shell —

1. Na, Ca
2. Mg, Fe
3. As, Bi
4. Rb, Sb

Answer: 3. Rb, Sb

Question 15. Which consists of particles of matter—

1. α -rays
2. β -rays
3. γ -rays
4. X-rays

Answer: 1.  -rays

Question 16. Which have two radial nodes-

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

Answer: 2. 3s

Question 17. The ratio of λα to λβ for the Balmer series of hydrogen spectra is given by

1. \(\frac{108}{80}\)
2. \(\frac{108}{90}\)
3. \(\frac{40}{54}\)
4. \(\frac{20}{27}\)

Answer: 1. \(\frac{108}{90}\)

Question 18. Indicate the conditions under which the ratio of Broglie wavelengths of a -particle and a proton will be—

1. When the ratio of their velocities is 4: 1
2. When the ratio of their velocities is 1: 8
3. When the ratio of their energies is 128: 1
4. When the ratio of their velocities is 1: 16

Answer: 2. When the ratio of their velocities is 1: 8

Question 19. Which ofthe following ions is paramagnetic—

1. Zn²⁺
2. Cu²⁺
3. He²⁺
4. ₂O²⁺

Answer: 2. Cu²⁺

Question 20. The energy of an electron in the first Bohr orbit of the H-atom is -13.6 eV. Then, which of the following statement(s) is/ are correct for He⁺ —

1. The energy of an electron in the second Bohr orbit is -13.6 ev
2. The kinetic energy of the electron in the first orbit is 54.46 ev
3. The kinetic energy of an electron in the second orbit is 13.6 ev
4. The speed of an electron in the second orbit is 2.19 × 10⁶ m.s^-1

Answer: 1. Energy electron in the second Bohr orbit is -13.6 ev

Question 21. For which of the following species, the expression for the energy of an electron in nth orbit, En = \(-\frac{13.6 Z^2}{n^2}\) eV. Atom-1. has the validity—

1. He²⁺
2. Li²⁺
3. Deuterium
4. Li²⁺

Answer: 2. He²⁺

Question 22. According to Bohr’s atomic theory, which of the following relations is correct—

1. The kinetic energy of electron oc z²/ n²
2. The product of the velocity of the electron and the principal quantum number α z²/n²
3. Frequency of revolution of the electron in an orbit z²/n³
4. Coulombic force of attraction on electron oc z³/n

Answer: 1. Kinetic energy of electron α z³/ n⁴

Question 23. Which is correct in the case of p -p-orbitals—

1. They are spherically symmetrical
2. They have strong directional character
3. They are three-fold degenerate
4. Their charge density along the x, y, and z -axes is zero

Answer: 2. They have strong directional character

Question 24. An isotone of \(\mathrm{f}_{32}^{76} \mathrm{Ge}\) is –

1. \({ }_{32}^{77} \mathrm{Ge}\)
2. \({ }_{33}^{77} \mathrm{As}\)
3. \({ }_{34}^{77} \mathrm{Se}\)
4. \({ }_{34}^{77} \mathrm{Se}\)

Answer: 2. \({ }_{33}^{77} \mathrm{As}\)

Question 25. Which of the following is correct—

1. Only the Lyman series is observed in both emission and absorption spectrum
2. The continuum in the line spectrum is noticed after a certain value of n
3. the wavelength of the mth line of Balmer Series is \(\frac{1}{\lambda}=R_H Z^2\left[\frac{1}{2^2}-\frac{1}{m^2}\right]\)
4. The number of spectral lines given when an electron drops from the 5th to the 2nd shell is six.

Answer: 1. Only the Lyman series is observed in both the emission and absorption spectrum.

Question 26. In Bohr’s models of atoms the lowest angular momentum, that an electron may have is

1. h
2. 0
3. \(\frac{h}{2 \pi}\)
4. \(\frac{h}{\pi}\)

Answer: 3. \(\frac{h}{2 \pi}\)

Question 27. Which one of the following is correct among the following sets of quantum number

1. \(n=1, l=2, m=1, s=\frac{1}{2}\)
2. \(n=3, l=1, m=0, s=\frac{1}{2}\)
3. \(n=5, l=1, m=2, s=\frac{1}{2}\)
4. \(n=4, l=1, m=-2, s=\frac{1}{2}\)

Answer: 2. \(n=3, l=1, m=0, s=\frac{1}{2}\)

Question 28. The number of total electrons in the n-th orbit of an atom is—

1. n
2. n2
3. 2n²
4. n-1

Answer: 3. 2n²

Question 29. Which of the following is the ground state electronic configuration of Cr (The atomic number of Cr is 24)—

1. ls²2s²2p⁶3s²3p⁶3d⁴4s²
2. ls²2s²2p⁶3s²z3p⁶3d⁵4s¹
3. ls²2s²2p⁶3s²3p⁶3d⁶
4. ls²2s²2p⁶3s²3p⁶3d³4s²4p¹

Answer:  2. ls²2s²2p⁶3s²z3p⁶3d⁵4s¹

Due to the half-filled electronic configuration of rf-subshell, Cr gets stabilized to a greater extent.

Question 30. The maximum how many number of electrons of the Cl atom follows the relation n + l = 3 —

1. 10
2. 8
3. 10
4. 16

Answer: 2.

n + Z = 3 represents 3s and 2p orbital. Electronic configuration of Cl: ls²2s²2p⁶3s²3p⁵

Question 31. Bohr’s theory does not apply to which of the following species?

1. H,
2. He²⁺
3.  Be³⁺
4. B⁴⁺

Answer:  2. He²⁺

Bohr’s theory does not apply to He²⁺ because it does not contain any electrons.