Physics – 5.2.3 Radioactive decay | e-Consult

During beta decay, a neutron within the nucleus is converted into a proton. This conversion involves the emission of a beta particle, which is an electron (e^-), and an antineutrino. The key change to the nucleus is that the atomic number of the resulting element increases by 1. This is because a neutron, being electrically neutral, transforming into a proton increases the number of positively charged particles (protons) in the nucleus. The mass number, however, remains the same because the mass of a proton is very close to the mass of a neutron. The mass difference is primarily accounted for by the kinetic energy of the emitted beta particle and the antineutrino. The antineutrino carries away a small amount of mass-energy.