Write down the postulates of Bohr atom model.

Answer

The energies of electrons are quantised
The electron is revolving around the nucleus in a certain fixed circular path called stationary orbit.
Electron can revolve only in those orbits in which the angular momentum (mvr) of the electron must be equal to an integral multiple of ` h//2pi` .
i.e.mvr` = nh//2pi`
Where n = 1, 2, 3, . . . . etc.
As long as an electron revolves in the fixed stationary orbit, it doesn't lose its energy.
However, when an electron jumps from higher energy state `(E_(2))` to a lower energy state `(E_(1))` the excess energy is emitted as radiation . The frequency of the emitted radiation is
`E_(2)-E_(1)=hv` and
`v= ((E_(2)-E_(1)))/(h)`
Conversely, when suitable energy is supplied to an electron, it will jump from lower energy orbit to a higher energy orbit .