Why do radioisotopes lying above the band building undergo beta decay?

Radioisotopes lying above the band of stability have an excess of neutrons compared to protons, which makes them unstable. To achieve a more stable ratio of neutrons to protons, these isotopes undergo beta decay, where a neutron is converted into a proton, emitting a beta particle (an electron) and an antineutrino. This process helps move the isotope closer to the band of stability on the nuclear chart. As a result, beta decay is a common mechanism for stabilizing isotopes that have a surplus of neutrons.