Identify the process defined as 'emission of an electron by an unstable nucleus'. - Leaving Cert Chemistry - Question 1 - 2018

The process defined as 'emission of an electron by an unstable nucleus' is known as beta decay (β-decay). This is a type of radioactive decay where a beta particle, which is essentially an electron, is emitted from the nucleus of an atom. In this decay process, a neutron in the nucleus is transformed into a proton, resulting in the emission of an electron (the beta particle) and an antineutrino. This transformation helps the nucleus to reach a more stable state.