The existence of positively charged nucleus at the centre of atom was first suggested by Rutherford in 1911 on the basis of his interpetation of observations made on scattering experiment. The main features of this model are :
(i) Atom is spherical and consists of two parts: Nucleus and extra-nuclear part.
(ii) The entire mass and entire positive charge is
concentrated in a very small region at the centre known as nucleus.
(iii) The space surrounding the nucleus known as
extranuclear part is negatively charged so an atom as a whole is neutral.
(iv) Most of extra-nuclear part is empty.
(v) The electrons are not stationary but are revolving around nucleus at very high speeds like planets revolving around the sun