A neutron changes into a proton emitting an electron and antineutrino, raising atomic number by 1.
Practise Atomic Structure & Periodicity All Atomic Structure & Periodicity topics
In beta-minus decay a neutron in the nucleus changes into a proton, emitting an electron and an antineutrino, so the atomic number increases by 1 and the mass number is unchanged. Beta-plus decay is the reverse, in which a proton changes into a neutron and emits a positron and a neutrino. Beta particles are more penetrating than alpha particles but are stopped by a few millimetres of aluminium. Beta decay is how nuclei adjust their neutron-to-proton ratio toward stability. It is driven by the weak nuclear force.
Key ideas: Beta minus: neutron becomes proton + electron + antineutrino, so Z rises by 1, A unchanged (14C to 14N). Beta plus: proton becomes neutron + positron + neutrino, Z drops by 1. Electron capture gives the same net change as positron emission. Beta-minus occurs in neutron-rich nuclei, beta-plus in proton-rich.
Common mistakes and connections: Students think the electron existed in the nucleus beforehand; it is created in the decay. Another is neglecting the neutrino, which carries away energy, so beta energies have a continuous spectrum. Beta particles penetrate moderately. Beta decay produces isobars, and connects to the weak force and quarks.
Carbon-14 decays to nitrogen-14 releasing 0.156 MeV shared between the electron and antineutrino as a neutron turns into a proton. The interactive lesson shows this as a live animation or chart.
Carbon-14 decays by beta-minus emission to nitrogen-14, as a neutron becomes a proton.
A neutron changes into a proton emitting an electron and antineutrino, raising atomic number by 1.
Beta Decay is a intermediate topic in Atomic Structure & Periodicity. It builds on the vocabulary of beginner topics in this area.
Study these earlier topics in Atomic Structure & Periodicity first: Mass Defect, Radioactivity, Alpha Decay.
The next topics in Atomic Structure & Periodicity are Gamma Radiation and Half-life.
Yes. The interactive lesson includes a self-check question on Beta Decay, and the Atomic Structure & Periodicity quiz draws on every topic in this area.
Beta Decay is topic 105 of 115 in Atomic Structure & Periodicity.