* Radioactivity comes from the nucleus: Radioactive substances have unstable atomic nuclei. These nuclei decay, releasing energy and particles (alpha, beta, gamma).

* Compounds involve bonding: Compounds are formed when atoms bond together. These bonds involve electrons, not the nucleus.

* Radioactivity depends on the isotope: It's not the element itself that's radioactive, but specific isotopes of that element. For example, carbon-14 is radioactive, but carbon-12 is not.

Here are some examples:

* Radioactive Iodine (I-131) in table salt (NaCl): While I-131 is radioactive, table salt is not because it contains mostly non-radioactive chlorine (Cl) and sodium (Na).

* Radioactive Uranium (U-235) in uranium hexafluoride (UF6): Uranium hexafluoride is used in uranium enrichment. Even though the uranium is radioactive, the compound itself is not inherently radioactive because the fluorine is non-radioactive.

In summary:

* A compound can be radioactive if it contains a radioactive element as part of its structure.

* A compound does not automatically become radioactive just because one of its constituent elements is radioactive.

It all depends on the specific isotopes involved in the compound.