Answer the following question given this paragraph: 

Radioactive decay is the process in which unstable nuclei become stable by emitting particles and energy and changing to different elements. There are three types of radioactive decay: alpha, beta, and gamma decay. Each differs in what is emitted, how far it can travel, and what it can penetrate.


Q: What is the process in which unstable nuclei become stable by emitting particles and energy and changing to different elements called?


A:
radioactive decay