What is a decay chain?

A decay chain refers to the series of radioactive decays that occur when a radioactive element transforms into one or more progeny radionuclides, ultimately leading to a stable end product. When a radioactive nucleus undergoes decay, it typically transforms into a different element or isotope that may itself be radioactive. This process continues through several steps—each decay creates a new element—until a stable element is achieved.

In the context of the correct answer, each step represents a transformation that decreases the energy of the system and often increases stability, as these transformations generally favor the production of stable isotopes. The concept of a decay chain is fundamental to understanding decay processes in nuclear physics and radiation safety, as it affects the management of radioactive waste and the assessment of radiation exposure over time.