The nuclei of radioactive isotopes can sometimes give off

• A. Alpha particles
• B. Beta particles
• C. Gamma rays
• D. Neutrons

Answer: (C)

When a nucleus in a radioactive isotope changes energy states, it can emit a gamma ray. After certain decays, the daughter nucleus is left in an excited state and relaxes to its ground state by releasing a high-energy photon—gamma radiation. This emission carries energy away without changing the nucleus’s composition, so the chemical identity stays the same. Gamma rays are a common form of radiation from radioactive nuclei and often accompany other decay processes. Alpha and beta emissions are charged particles that can occur in other decays, and neutron emission happens in specific nuclear reactions, but gamma radiation specifically arises from transitions between energy states within the nucleus itself.