Nuclear instability (A-level only)

Graph of N against Z for stable nuclei.

Possible decay modes of unstable nuclei including α, β⁺, β⁻ and electron capture.

Changes in N and Z caused by radioactive decay and representation in simple decay equations.

Questions may use nuclear energy level diagrams.

Existence of nuclear excited states; γ ray emission; application eg use of technetium-99m as a γ source in medical diagnosis.