When an electron in a neutral atom captures another free electron, the process is known as electron capture. Electron capture occurs when an atomic nucleus captures an electron from its surrounding electron cloud or from the immediate vicinity.
During electron capture, a proton in the nucleus combines with an electron, resulting in the conversion of the proton into a neutron. This process effectively reduces the atomic number of the atom by one, as a proton is transformed into a neutron. The atom undergoes a change in its identity and becomes an atom of a different element.
To maintain overall charge neutrality, the electron that is captured comes from the electron cloud surrounding the atom. The electron cloud readjusts to account for the captured electron, filling the energy level or orbital previously occupied by the captured electron.
The energy released or absorbed during electron capture varies depending on the specific atom involved. In some cases, the process is accompanied by the emission of gamma radiation, which is a high-energy electromagnetic radiation.
Electron capture is often observed in radioactive isotopes, where the nucleus is unstable and seeks to achieve a more stable configuration by capturing an electron. This process helps to stabilize the nucleus by decreasing the ratio of protons to neutrons.