êRutherford studies radiations emitted from uranium and thorium and named them alpha and beta. His discoveries came as a result of Henri Becquerel's discovery of radiation.

Rutherford "gold foil" experiment 1911

Using alpha particles as atomic bullets, he probed the atoms in a piece of thin gold foil (.00006 cm). After this experiment, he came up with the concept of protons, small positively charged particles that must be in the atome. These alpha particles were named by Rutherford after the advent of the discovery of radioactivity.