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Beta decay
Intermediate
Neutron changes to a proton, emitting an electron and antineutrino.
β⁻: a neutron becomes a proton emitting an electron and antineutrino; β⁺: a proton becomes a neutron with positron and neutrino. Energy is shared continuously, so neutrinos were proposed by Pauli.
Carbon-14 → nitrogen-14.
Electron isn't in the nucleus beforehand.
In more detail
Beta decay changes a neutron into a proton or vice versa, emitting an electron or positron along with a neutrino. The atomic number changes by one, while the mass number stays the same.
Real-world uses
- Beta emitters are used in medical tracers and thickness gauges.
- Carbon-14 decays by beta emission, which is used for dating.
- Carbon-14 decays by beta emission, which is used to date organic material in archaeology.
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Frequently asked questions
Why is a neutrino emitted?
To conserve energy, momentum and spin in the decay.
Is beta decay the same as an electron from the nucleus?
The electron is created in the decay, not already present in the nucleus.
What happens to the nucleus in beta decay?
A neutron turns into a proton, emitting an electron and an antineutrino, so the atomic number increases by one.
Related topics in Atomic & Nuclear Physics
Nuclear force · Radioactivity discovery · Alpha decay · Gamma decay · Radioactive decay law · Half-life