Question

Why Rutherford's model of atom is unstable

Answer 1

All of the negative charge was held in the electrons, which must orbit the dense nucleus like planets around the sun. In 1912 Bohr joined Rutherford. He realized that Rutherford's model wasn't quite right. By all rules of classical physics, it should be very unstable.

Answer 2

Rutherford established that the mass of the atom is concentrated in its nucleus .The light , negatively charged , electrons circulated around this nucleus , much like planets revolving around the sun
After working with both Thomson and Rutherford , Niels Bohr , in 1913 , released that Rutherford's model was unstable