What happens to an atom at the end of radioactive decay?

• A. It becomes unstable and more radioactive
• B. It suddenly splits into multiple atoms
• C. It releases energy and becomes lighter
• D. It releases excess energy and becomes stable (no longer radioactive)

Answer: (D)

Radioactive decay is the process by which an unstable nucleus rearranges into a more stable configuration, shedding excess energy as radiation or particles. That energy is the difference between the unstable state and the more stable state, and the new nucleus is typically more tightly bound. Once the final product in a decay series is reached, it is stable and no longer radioactive.