5.4. Nuclear Radioactivity (E3 - AHL)

Isotopes are more stable when there is a balanced ratio of protons to neutrons and a high binding energy per nucleon.

Strong nuclear force holds nucleons together, but large nuclei experience greater repulsive electrostatic forces, leading to instability.

Nuclei can undergo alpha decay, beta decay, or gamma emission to achieve a more stable energy configuration.

Alpha decay reduces both mass and charge by emitting a helium nucleus, decreasing nuclear size.

Beta decay changes a neutron into a proton (or vice versa), adjusting the proton-neutron ratio for greater stability.

Gamma decay allows the nucleus to release excess energy without changing its composition, often following alpha or beta decay.

Although each individual decay is random and spontaneous, the overall behavior of a large sample follows a predictable half-life pattern.

Activity (A) and count rate decrease exponentially, and predictions about the remaining quantity of radioactive material can be made using the number of half-lives.

Statistical laws ensure accurate average behavior, even though specific decay events are unpredictable.