What was rutherford's contribution to our knowledge of atoms

He proposed the theory of the structure of atoms
(1)The nucleus at the centre of the atom has the positive charge.Most of the mass of the atom is concentrated in the nucleus.
(2)The negatively charged electrons revolve around the nucleus in specific orbits
(3)In comparison with the size of the atom , the nucleus is very very small.

Hello! i️ believe a.) is the correct answer. : )