Explain Bohr’s model of hydrogen atom and its limitations.

Explanation

Niels Bohr proposed that
a) electrons in an atom occupy stationary orbits of fixed energy (K, L, M, N, .. . ) at different distances from the nucleus.
b) when an electron jumps from a lower energy state to higher energy state, it absorbs energy or emits energy when such a jump occurs from a higher energy state to lower energy state.
c) the energies of an electron in an atom can have only certain values `E_(1) , E_(2) , E_(3)`,......... i.e. the energy is quantized. The states corresponding to these energies are called stationary states and the possible values of the energy are called energy levels.
d) the angular momentum of electron is multiple integral of `(L)/(2pi)` .
`therefore L = m v r = (nh)/(2pi)`
m =mass of electron , v= velocity of electron , r = radius of circular path , h = plank constant
Limitations :
1) Bohr's model failed to account for splitting of line spectra (Zeeman effect).
2) This model failed to account for the atomic spectra of atoms of more than one electron.
3) Bohr theory was not explained the quantisation of angular momentum of an electron .
4) It was not explained the formation of chemical bonds.