Which term is used to describe isotopes of atoms that have unstable nuclei and undergo radioactive decay?

• A. Ions
• B. Isomers
• C. Radioisotopes
• D. Allotropes

Answer: (C)

Verified step by step guidance

1. Understand the definitions of the given terms: Ions are atoms or molecules that have gained or lost electrons, resulting in a net charge.
2. Isomers are molecules with the same molecular formula but different arrangements of atoms in space.
3. Allotropes are different structural forms of the same element in the same physical state (e.g., graphite and diamond for carbon).
4. Radioisotopes are isotopes of atoms that have unstable nuclei and undergo radioactive decay, emitting radiation to reach a more stable state.
5. Therefore, the term that describes isotopes with unstable nuclei undergoing radioactive decay is 'Radioisotopes'.