What does radioactive decay refer to?

Radioactive decay refers to the process by which unstable atomic nuclei lose energy by emitting radiation. This process can involve the release of particles, such as alpha particles, beta particles, and gamma rays. As the unstable nucleus transforms into a more stable form, it effectively reduces its energy state. This phenomenon is fundamental to understanding how certain elements decay over time, transforming into different elements or isotopes while releasing radiation. This definition highlights the nature of radioactive decay as a key concept in nuclear chemistry and physics.

Other options touch on related concepts, but they do not accurately represent what radioactive decay entails. Bonding between atoms refers to chemical interactions rather than nuclear changes, the transformation of an element could imply a broader range of processes that aren't specific to the context of decay, and the accumulation of non-decayed materials does not convey the active process of change that occurs during radioactive decay.