Explain Bohr's atomic model.

(N/A) In $1913$,Bohr concluded that despite the success of electromagnetic theory in explaining large-scale phenomena,it could not be applied to processes at the atomic scale.
Concepts different from classical mechanics and electromagnetism were needed to understand the structure of atoms and the relation of atomic structure to atomic spectra.
Bohr combined classical and early quantum concepts and proposed his theory in the form of three postulates:
$(1)$ An electron in an atom could revolve in certain stable orbits without the emission of radiant energy,contrary to the prediction of electromagnetic theory. Each atom has certain definite stable states in which it can exist,and each possible state has a definite total energy. These are called the stationary states of the atom.
$(2)$ The electron revolves around the nucleus only in those orbits for which the angular momentum is an integral multiple of $\frac{h}{2 \pi}$,where $h$ is Planck's constant $(6.626 \times 10^{-34} \ J \ s)$. Thus,the angular momentum $(L)$ of the orbiting electron is quantized.
That is,$L = \frac{nh}{2\pi} = mvr$,where $n = 1, 2, 3, ...$
$(3)$ Bohr's third postulate incorporated early quantum concepts developed by Planck and Einstein. It states that an electron might make a transition from one of its specified non-radiating orbits to another of lower energy. When it does so,a photon is emitted having energy equal to the energy difference between the initial and final states.
The frequency $(v)$ of the emitted photon is given by:
$hv = E_i - E_f$
$\therefore v = \frac{E_i - E_f}{h}$
Where $E_i$ is the energy of the initial state,$E_f$ is the energy of the final state,and $E_i > E_f$.