Bohr’s Atomic Model

Bohr stated the following postulates for the structure of the atom:

1. Atom has fixed orbits where electrons revolve around the nucleus

2. The orbitals have fixed energy and are called shells (K,L,M,N shells).

3. The energy levels are shown by integer n (1,2,3… ) known as quantum number.

4. Electrons do not absorb or release energy in a particular orbit.

5. Excitation or de excitation of electron from one orbit to the other causes energy gain or loss.

    ΔE = $E_2 \: - E_1$
   

6. This emitted or absorbed energy is discontinuous and is called a photon ( ΔE = 1 photon)

7. Stationary state were present in those orbits in which angular moment of electron would be integral multiple of $\frac {h}{2π}$ (where h is planks constant).

Limitation of Bohr's atomic model:

Bohr’s model was a huge advancement in the structure of atom but still came with certain limitations.

1. Bohr’s atomic model failed to explain the Zeeman Effect (effect of magnetic field on the spectra of atoms).

2. It failed to explain the Stark effect (effect of electric field on the spectra of atoms).

3. It deviates the Heisenberg Uncertainty Principle.

4. It could not explain the spectra of larger atoms.

5. It only explained the monoelectronic species.