3.8.1.3
Beta-minus decay keeps A constant and increases Z by 1
Nuclear Structure & Radiation — AQA A-Level Physics
- Occurs when the nucleus has too many neutrons.
- A neutron converts to a proton, emitting an electron and an anti-electron neutrino.
$${}^{A}_{Z}X \rightarrow {}^{A}_{Z+1}Y + {}^{0}_{-1}\beta + \bar{\nu}_e$$
- $A$: nucleon number (unchanged)
- $Z$: proton number of parent
- $Y$: daughter nucleus
- $β$: beta-minus particle (electron)
- $ν̄ₑ$: anti-electron neutrino
- Nucleon number (A) stays the same. Proton number (Z) increases by 1. Neutron number (N) decreases by 1.
- On the N-Z graph: N decreases by 1, Z increases by 1 — the point moves one step diagonally down-right.