In his Gold Foil experiment, few particles were deflected strongly, where as he thought all particles will go straight through the foil (some did though, which are called electrons.) J. J. Thompson, Rutherford's former teacher, proposed that if there are negative charge particles (he named them electrons), there must also be a positive charge particles; Rutherford proved his theory right, and he called the positive charge protons. He also found that inside the atom, there must be a positive charge that is clustered in a tiny region in its center, which is called the nucleus.
