An alpha-particle two neutrons.
Alpha particle is alternatively known as Alpha radiation or Alpha ray is a positively charged particle emitted from the decay of various radioactive material. Alpha particle mass is due to the two protons and two neutrons bonding. Thus, the Alpha ray nucleus is very similar to the Helium-4 nucleus. The alpha particle is denoted by the Greek alphabet α.
How does alpha decay occur?
Alpha decay occurs most often in heavy nuclei that have too large a proton to neutron ratio. An alpha particle, with its two protons and two neutrons, is a very stable configuration of particles. Alpha radiation decreases the ratio of protons to neutrons in the parent nucleus, inducing it to a more stable configuration. Many nuclei heavier than lead decay by this process.