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