Write three postulates of Bohr. Mention two limitation of Bohr model.

Explanation

Postulates :
1. The electrons revolve only in certain orbits called stationary orbits without the emission of radiant energy.
2. The angular momentum of an electron in the stationary orbit is an integral multiple of `h/(2pi)`
i.e., `L = (nh)/(2pi)`
where , n = 1, 2, 3 .......(Principle quantum number)
h = plank.s constant.
3 The atom radiates energy only when an electron jumps from one stationary orbit of high energy to another or lower energy `E_(2)-E_(1) = hv` or
`v = (E_(2)-E_(1))/h " or " E = E_(2) - E_1`
Limitations:
1. This theory is applicable only to hydrogen and hydrogen like atoms.
2. It could not explain relative intensities of spectral lines.
3. It could not explain elliptical orbits of electron.
4. It could not explain stark effect 5. It could not explain zeeman effect
6. It could not explain wave nature of electrons.