Question

Which of the following is true for Bohr's model?

• A. An electron can move only in those orbits for which its angular momentum is an integral multiple of $\frac{h}{2\pi }$
• B. Electrons revolve around nucleus in discrete and quantized energy levels/orbits.
• C. The energy of an electron in the orbit do not change with time.
• D. Electron will move from a lower stationary state to a higher stationary state when required amount of energy is absorbed.

Answer 1

Answer: (A), (B), (C), (D)

Electron will move from a lower stationary state to a higher stationary state when required amount of energy is absorbed.

The main postulates of Bohr's theory was:

a. The electron in the hydrogen atom revolves around the nucleus in a circular path of fixed radius and energy. These paths are called orbits, stationary states, energy shells, or allowed energy states. These stationary states for electrons are numbered as n = 1, 2, 3, . . . . . or designated as K, L, M, N, . . . . . etc. shells. These integral numbers are known as principal quantum numbers. These orbits are arranged concentrically around the nucleus.

b. Electrons revolve only in those orbits where the angular momentum of the electron is quantized. Thus an electron can move only in those orbits for which its angular momentum is an integral multiple of h/2π that is why only certain fixed orbitals are allowed.

$m_{e}vr$ = $\frac{nh}{2\pi }$, or $r$ = $\frac{nh}{2m_{e}v\pi }$ (where $n=1,2,3andsoon.$)

d. The electron will move from a lower stationary state to a higher stationary state when the required amount of energy is absorbed by the electron. When the electron jumps back to the lower energy level, it emits the same amount of energy. The energy change does not take place in a continuous manner.