There are three main types of nuclear radiation emitted from radioactive atoms:
Alpha and beta radiation consist of actual particles that are electrically charged and are commonly referred to as alpha particles and beta particles.
Alpha particles consist of two protons and two neutrons tightly bound together. Beta particles are high energy electrons that are generated when a neutron in a nucleus splits to form a proton and an accompanying electron.
Gamma radiation, however, belongs to a class known as electromagnetic radiation. Electromagnetic radiation consists of energy transmitted in the form of waves.