beta decay The radioactive decay of an unstable atom by the emission of a negatively charged beta particle (negatron) from the nucleus, often accompanied by the emission of radiant energy (gamma rays). Beta decay may be regarded as the alteration of a neutron into a proton and an electron. As a result of beta decay the atomic number of the atom is increased by one, while the neutron number is decreased by one (e.g. C¹⁴₆ → N¹⁴₇).

beta decay Some unstable atoms decay by emitting a negatively charged beta particle (negatron) from the nucleus, often accompanied by the emission of radiant energy (gamma rays). Beta decay may be regarded as the alteration of a neutron into a proton and an electron. As a result of beta decay the atomic number of the atom is increased by one, while the neutron number is decreased by one.