Drawbacks of Bohr atomic model.

1. Bohr treated electrons as particles where according to de Broglie's hypothesis, having a very low mass, electron also exhibits wave nature.

2. Bohr's model was adequate only for nucleus having only one electron e.g. Hydrogen, He+1, Li+2 etc. Bohr's model could not explain the spectra of multi-electronic atoms.

3. Bohr's model was two-dimensional where an atom is three-dimensional.

4. Using a better spectrometer, the spectra showed very fine lines. Bohr's model could not explain the origin of those fine lines. (Solved by Arthur Sommerfield who imagined electrons orbiting in different planes and having elliptical orbits.)

5. Bohr's model could not explain the effect electric field and magnetic field on spectra. (Stark effect and Zeeman effect)

6. In Bohr's equation, the momentum and position of electron, revolving around the nucleus were well defined. But, according, Heisenberg's Uncertainty principle, it is impossible to measure the position and momentum of electrons precisely. If the position is measure with maximum precision, there will be uncertainty in the value of momentum and vice versa.