Give the main postulates of Bohr's model of an atom.

To overcome the limitations of the Rutherford model of an atom in 1913 Neil’s Bohr suggested an atomic model which tells that electrons can be found only in certain energy levels around the nucleus. The main postulates of Bohr's model of an atom are as follows:

1. The electron revolves around the nucleus in certain discrete circular orbits of atom. These orbits or shells are called energy levels. The figure below shows energy levels of atom.

2. While revolving in these discrete orbits the electron do not radiate energy and this is the reason why electron do not fall in the nucleus.

3. The electron orbits or shells are represented by letters K,L,M,N etc or numbers n = 1,2,3 and so on this is shown in figure below.

4. An electron revolving in a particular orbit, in gaining a certain amount of energy, jumps to the next orbit and vice versa.