Flexi Says: Alpha particles, also called as alpha rays, are positively charged particles that consist of two protons and two neutrons bound together into a particle which is identical to the nucleus of a helium-4 atom. In Rutherford's gold foil experiment of most of the alpha particles were passed right through the foil without any deflection. However, due to the positively charged protons which are located in the nucleus at the center of the atom, a very small percentage (about 1 in 8000 particles) bounced off the gold foil at very large angles. Some were even redirected back toward the source.
