Which term describes the energy emitted by a radioactive atom during decay?

• A. Isotope
• B. Activation
• C. Decay chain
• D. Radiation

Answer: (D)

Energy released during radioactive decay is radiation. This energy can take the form of particles such as alpha or beta particles, or as electromagnetic waves like gamma rays as the nucleus shifts toward a more stable state. The other terms refer to different ideas: an isotope is a variant of an element with a different number of neutrons; activation is when a material becomes radioactive due to exposure to radiation; a decay chain is the sequence of successive decays a nuclide may undergo before reaching stability. Radiation is the umbrella term for the energy emitted in the decay process.