"radioactive decay." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/radioactive-decay>.
radioactive decay. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/radioactive-decay
The spontaneous transformation of an unstable atomic nucleus into a lighter one, in which radiation is released in the form of alpha particles, beta particles, gamma rays, and other particles. The rate of decay of radioactive substances such as carbon 14 or uranium is measured in terms of their half-life.