Electron capture

Definition

Electron capture is a type of radioactive decay in which an inner orbital electron is captured by the nucleus of its own atom. This process decreases the atomic number by one and usually results in the emission of an X-ray photon or Auger electron.

5 Must Know Facts For Your Next Test

1. Electron capture reduces the atomic number by one while keeping the mass number unchanged.
2. It is commonly observed in proton-rich nuclei where it helps achieve a more stable neutron-to-proton ratio.
3. The captured electron usually comes from the K-shell (innermost shell) of the atom.
4. The process often results in the emission of either an X-ray photon or an Auger electron as the atom rearranges itself to fill the vacancy left by the captured electron.
5. Electron capture can be represented by: $p + e^- \rightarrow n + \nu_e$, where $p$ is a proton, $e^-$ is an electron, $n$ is a neutron, and $\nu_e$ is an electron neutrino.

Review Questions

• What happens to the atomic number and mass number during electron capture?
• From which shell does the captured electron typically come during electron capture?
• What kinds of radiation are typically emitted as a result of electron capture?

Related terms

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

Beta Decay:

A nuclear decay process where a beta particle (electron or positron) is emitted from an atomic nucleus.

$\gamma$-Ray Emission: $\gamma$-rays are high-energy photons released from excited nuclei as they transition to lower energy states.