Inside elements
Chemistry is concerned with the exchange of electrons in the outside regions of an atom, rathe than with what is happens in the core of an atom, in tthe necleus. However, when working with radioactive elements, scientists, and physicist need to understand the nature of the particles that make up the atoms.
Radioactive elements vary greatly. All are quite rare; mast are metals. But radioactive isotopes cannot be used in the same way as other metals - to make new materials. indeed, if we use this way they could make rather dangerous materials. Rather, radioactive elements are used for their radioactive properties alone.