Rutherford's model of an atom

cRutherford’s Model of Atom (By Ernest Rutherford in 1909)

This was based on an experiment in which α – particles were bombarded on a thin gold foil.

Observations of Rutherford’s α-particle scattering experiment are:

(a) Most of the α – particles passed without any hindrance.

(b) Some of the α – particles deflected from their original path at a noticeable angle.

(c) Very few of the α – particles bounced back at their original path.

Postulates of Rutherford’s Model of Atom:

(a) Most of the part in an atom is empty.

(b) There is a positively charged center in atom, which contains nearly the whole mass of atom. The centre is called nucleus.

(c) The size of nucleus is very small compared to an atom.

(d) Electrons revolve round the nucleus.

Drawbacks of Rutherford Model

(a) According to Rutherford’s Model, electron revolves round the positively charged nucleus which is not expected to be stable. But a charged particle in an accelerated motion along a circular path would continuously undergo loss of energy and finally would fall into nucleus. This makes an atom unstable while atoms are quite stable.

(b) Rutherford model could not solve the problem of atomic mass of atom as it proposed only the existence of protons in the nucleus.