Discovery of protons and electrons supported the fact that atoms are divisible. Dalton’s atomic theory suggested that atoms were indestructible and indivisible. But the discovery of two fundamental particles- protons and electrons inside the atom, led to the failure of this aspect of Dalton’s atomic theory. It was necessary to find out the arrangement of electron and protons within the atom. There were a lot experiments done to prove the presence of these particles within the atom. J.J. Thomson proposed the model of atom as a positively charged sphere in which the electrons were embedded. Further experiment by Rutherford proved that the atom has a positively charged nucleus at the center in which the mass of an atom resides. The negatively charged electrons revolve around the nucleus.