Describe Rutherford atom model. What are the draw backs of this model.

Explanation

Rutherford atom model : The essential features of Rutherford's nuclear model of the atom or planetary model of the atom are as follows :
1) Every atom consists of tiny central core, called the atomic. nucleus, in which the entire positive charge and almost entire mass of the atom are concentrated.
2) The size of nucleus is of the order of `10^(-15)`m, which is very smali as compared to the size of the atom which is of the order of `10^(-10)`m.
3) The atomic nucleus is surrounded by certain number of electrons. As atom on the whole is electrically neutral, the total negative charge of electrons surrounding the nucleus is equal to total positive charge on the nucleus.
4) These electrons revolve around the nucleus in various circular orbits as do the planets around the sun. The centripetal force required by electron for revolution in provided by the electrostatic force of attraction between the electrons and the nucleus.
Draw backs : According to classical E.M. theory.
1) The revolving electron loses energy continuously, it must spiral inwards and eventually fall into the nucleus. As matter is stable, we cannot expect the atoms to collapse.
2) Since the frequency of radiation emitted is tlie same as the frequency of revolution, the atom should, radiate a continuous spectrum, but what we observe is only a line spectrum.