Which process is described by splitting a heavy nucleus into lighter fragments to reach stability?

• A. Fission
• B. Fusion
• C. Radioactive decay
• D. Neutron capture

Answer: (A)

This describes nuclear fission. Heavy nuclei have relatively low binding energy per nucleon, so splitting them into lighter, more stable fragments increases the total binding energy and releases energy. The process often produces additional neutrons, which can sustain a chain reaction in a reactor or bomb. For context, the binding energy curve shows mid‑mass nuclei around iron‑56 are most stable; moving from very heavy to lighter fragments moves the nucleus toward that stability peak, releasing energy in the process. Fusion, by contrast, combines light nuclei into heavier ones; radioactive decay is about an unstable nucleus shedding particles to become more stable without splitting a heavy nucleus; neutron capture adds a neutron rather than splitting the nucleus.