Electron capture

Definition

Electron capture is a process in which an atomic nucleus absorbs an inner orbital electron, leading to the conversion of a proton into a neutron and the emission of a neutrino. This process reduces the atomic number by one while keeping the mass number unchanged.

5 Must Know Facts For Your Next Test

1. Electron capture occurs when an electron from the closest orbital (usually the K-shell) is absorbed by the nucleus.
2. This process results in a decrease of one in the atomic number but does not change the mass number.
3. A neutrino is emitted during electron capture, but this particle has very little mass and no charge.
4. Electron capture can compete with positron emission if the energy difference between parent and daughter nuclei is less than 1.022 MeV.
5. The resulting atom after electron capture often emits characteristic X-rays or Auger electrons as it relaxes to its ground state.

Review Questions

• What happens to an atomic nucleus during electron capture?
• How does electron capture affect the atomic number and mass number of an element?
• What particles are emitted as a result of electron capture?

Related terms

Positron Emission: A type of radioactive decay where a proton in the nucleus is converted into a neutron, releasing a positron and a neutrino.

$\beta$ Decay: A type of radioactive decay in which a beta particle (an electron or positron) is emitted from an atomic nucleus.

$\gamma$ Emission: $\gamma$ rays are high-energy photons emitted from a nuclear transition, typically following other types of radioactive decay like $\alpha$ or $\beta$ decay.