“Bohr’s Model” MCQ with Answer Explanation.

51. How many total orbitals are present in the first energy level (n=1) of an atom according to the Bohr model?

A) 1
B) 2
C) 3
D) 4

Answer: A) 1.

Explanation: The first energy level (n=1) contains only one s orbital.

52. Which factor does not affect the energy levels of an electron in the Bohr model?

A) Nuclear charge
B) Electron mass
C) Distance from the nucleus
D) Temperature

Answer: D) Temperature.

Explanation: In the Bohr model, temperature does not directly affect the quantized energy levels of an electron.

53. In a hydrogen atom, which transition would result in the highest energy photon being emitted?

A) n=3 to n=2
B) n=2 to n=1
C) n=4 to n=3
D) n=5 to n=4

Answer: B) n=2 to n=1.

Explanation: The transition from n=2 to n=1 releases the most energy, resulting in a high-energy photon.

54. What type of quantum number is the principal quantum number (n)?

A) Angular momentum quantum number
B) Magnetic quantum number
C) Principal quantum number
D) Spin quantum number

Answer: C) Principal quantum number.

Explanation: The principal quantum number (n) defines the size and energy of the electron’s orbit.

55. Which of the following accurately reflects the relationship between energy levels in a hydrogen atom?

A) Energy levels increase linearly with n.
B) Energy levels are spaced equally.
C) Energy levels become closer together as n increases.
D) Energy levels are unpredictable.

Answer: C) Energy levels become closer together as n increases.

Explanation: As the principal quantum number (n) increases, the energy levels become closer, indicating a decrease in energy difference.

56. In the context of the Bohr model, what determines the color of light emitted from an atom?

A) The mass of the atom.
B) The type of gas used.
C) The energy difference between electron levels.
D) The temperature of the atom.

Answer: C) The energy difference between electron levels.

Explanation: The color of emitted light corresponds to the specific energy difference between transitions of electrons.

57. Which series corresponds to transitions in hydrogen that emit visible light?

A) Lyman series
B) Balmer series
C) Paschen series
D) Brackett series

Answer: B) Balmer series.

Explanation: The Balmer series consists of transitions that fall within the visible spectrum.

58. How is the electron cloud model different from the Bohr model?

A) It uses circular orbits.
B) It defines specific paths for electrons.
C) It incorporates probability distributions for electron positions.
D) It does not consider quantum mechanics.

Answer: C) It incorporates probability distributions for electron positions.

Explanation: The electron cloud model represents electrons as probabilities, rather than fixed orbits, highlighting their wave-like nature.

59. What does a higher principal quantum number (n) indicate about an electron’s energy?

A) It is lower.
B) It is higher.
C) It remains constant.
D) It is negative.

Answer: B) It is higher.

Explanation: A higher principal quantum number indicates an electron is in a higher energy level, further from the nucleus.

60. Which of the following statements is true about the Bohr model?

A) It applies universally to all atoms.
B) It accurately describes electrons as particles only.
C) It quantizes energy levels and angular momentum.
D) It neglects the concept of quantization.

Answer: C) It quantizes energy levels and angular momentum.

Explanation: The Bohr model introduces quantization, a key concept in understanding atomic structure and electron behavior.