^Limitations of Bohr’s theory
- It is valid only for single electron system.
- Nucleus was taken as stationary but it also rotates about its own axis.
- Couldn’t explain fine structure of spectral line.
- Provides no information about the relative intensities of spectral lines.
- Provides no distribution of electrons in an atom.
- Fails to explain that why do the electrons move only in circular orbits.
- Bohr’s theory doesn’t explain the Zeeman effect (splitting up of spectral lines in magnetic field) & Stark effect (splitting up of spectral lines in electric field).
- Bohr’s theory doesn’t explain the doublets in the spectrum of the some atoms e.g. in sodium (5890 A0 & 5896 A0).
- Silent about the selection rules which governs the transitions.
- Use two theories
(i) Quantum (to explain the existence of stationary orbits) &
(ii) Classical (for motion of electrons in the orbits). These two theories essentially oppose each other.