The model of an atom supported by J.J.Thomson after discovering electrons in 1897. Also known as plum-pudding model of an atom as a system of positively charged particles with embedded electrons which have negative electric charge (thus, the atom remains electrically neutral). Was replaced by the Rutherford's planetary atomic model in `1908 in which atoms are considered to have a solid nucleus surrounded by electrons moving around like planets around the sun. In his experiment Rutherford bombarded a strip of gold foil with alpha particles (nuclei of helium atom) and observed their distribution after the collision with atoms of gold. Distribution pattern showed that some of alpha particles were scattered at different angles (some were bounced back), while many others have passed through. That means, atoms have a positively charged nucleus that occupies a very small space.