Beta decay
There are two types of beta decay: beta plus decay and beta minus decay. Only beta minus decay, however, occurs naturally[1].
Beta minus decay occurs in unstable nuclei with too many neutrons. One of the neutrons becomes a proton in a process that involves the release of a β- particle (a high energy electron) and an antineutrino. The result is the nuclei of a different element. This element is located one box to the right of the original element on the periodic table [1].
Beta plus decay occurs in unstable nuclei with too many protons. One proton becomes a neutron with the release of a β+ particle (a positron) and a neutrino. The result of this decay is the nuclei of a different element, which is located one box to the left of the original element on the periodic table[1].