Atom Rutherford Model:
Rutherford's experiment on the scattering of α -particles proved that the positive charge could be distributed evenly throughout the whole mass of the atom. If a thin gold foil is placed in the path of α-particles from the radio-active material, the particles are scattered and in some cases the α -particles are scattered through large angles. Rutherford came to the conclusion that positively charged α -particles must be encountering extremely dense concentrations of the positive charge at the centre of the atom. If a number of bullets are fired through a sand-bag containing a stone, some of the bullets striking the stone will be scattered. Thus, Rutherford considered the atom to be consisting of a nucleus containing a positive charge at its centre. The electrons were considered to be distributed around the nucleus in the empty space of the atom. Thus, the discovery of the nucleus of the atom is due to Rutherford. The nucleus is of great importance to explain the modern experimental and theoretical facts.
Drawback:
The planetary electron is constantly attracted towards the nucleus. The accelerated electron must emit the electromagnetic radiations. If the electron emits electro-magnetic radiations as it revolves, it will finally be drawn nearer the nucleus. As the electron spirals down to the nucleus, it must emit electromagnetic waves of all frequencies. This fact is contrary to the experimental results. Moreover, according to Rutherford's model, electrons can revolve in any orbit of any radius and thus emit electromagnetic radiations of all frequencies. This also is contradictory to the experimental results. Experimentally, it has been found that atoms, like hydrogen atoms emit line spectra of fixed frequencies only and not of all frequencies. This led Bohr to design a new model of the atom.