What is the series of reactions triggered by the splitting of a nucleus that releases neutrons called?

The series of reactions triggered by the splitting of a nucleus that releases neutrons is known as a chain reaction. In nuclear fission, when a heavy nucleus splits, it releases energy and additional neutrons. These released neutrons can then induce fission in nearby nuclei, leading to a self-sustaining sequence of reactions, which is characteristic of a chain reaction. This process is fundamental to the operation of nuclear reactors and atomic bombs.

While nuclear fusion refers to the process where two light atomic nuclei combine to form a heavier nucleus, and ionization involves the removal of electrons from atoms or molecules, neither relates to the concept of nucleons splitting and causing further reactions. Understanding the distinction between these terms is crucial in the context of nuclear reactions.