Bhor Atomic Model Postulates

                                              

Bohr’s Postulates

In order to explain the stability of the atom and line spectra. Bohr suggest a set of Postulates

1. An electron In an atom revolves around the nucleus in a circular orbit. The force between the electron and the nucleus provide the necessary centripetal force for the circular motion.

2. The electron revolve in the certain orbital for which the angular momentum is an integral multiple of  h/2Π. the allowed orbitals are given by

                        mvr=   h/2Π         …………………(1)

Where

n is an integer (1,2,3,4…………….)

h is Plank constant value of h is 6.610^-34Js.

This Postulate is known as the quantization of the angular momentum.

3.  The electron moving in an allowed orbit dose not radiate energy. Therefore the total energy of the electron remain constant in an allowed orbit in an atom.

4. Electromagnetic radiation is emitted when the electron jump from high energy orbital to lower energy orbital

The frequency v of the emitted radiation is given as

Let E₁ is the energy of the higher energy orbital.

And E₂ is the energy of lower energy orbital now the frequency is given by

                       V=E₁-E₂/h     ……………………..(2)

Equation (2) represent the Bohr’s frequency condition