What is the term used for energy released when an atom splits?

The term for the energy released when an atom splits is best represented by the concept of nuclear fission, which is often confused with other processes related to atomic interactions. None of the options provided directly mention "fission," but the closest term applicable to energy release in nuclear processes is indeed related to the energy derived from atomic changes.

Radiation, the selected answer, refers generally to the energy that is emitted in various forms, including gamma rays or particles, during nuclear reactions, including both fission and fusion. In the context of fission, when an atom splits, it releases energy along with radiation, as smaller fragments and additional neutrons are produced. This radiation is indicative of the energy transformations occurring during the process.

The other terms, while related to atomic and nuclear processes, do not directly describe the energy produced by the splitting of atoms in the same way. Nuclear fusion involves the combining of atomic nuclei, radioactive decay refers to the spontaneous decomposition of a nucleus, and isotopic conversion relates to transforming one isotope into another without specifying the energy aspect tied to the splitting of an atom. Understanding nuclear fission involves acknowledging how radiation plays a role in the energy exchange during that splitting process.