Radiochemistry is the chemistry of radioactive materials, where radioactive isotopes of elements are used to study the properties and chemical reactions of non-radioactive isotopes (often within radiochemistry the absence of radioactivity leads to a substance being described as being inactive as the isotopes are stable Nuclei that are not stable spontaneously break apart and in the process emit smaller particles while leaving behind a nucleus of a lighter element. This phenomenon is called radioactivity and the process itself is a radioactive decay. Radioactive isotopes are simply called radioisotopes.Radiochemical Methods Radiochemical methods of analysis depend on the specific properties of certain . These properties include the type and energy of the radiation emitted, the half-life (t1/2), and the decay schemes of that particular nuclide. ... It involves the preparation of the analyte in a radioactive form.