Carbon-15 undergoes beta decay primarily because it has an unstable nucleus. Beta decay occurs when there is an imbalance between the number of protons and neutrons in the nucleus of an atom.
In the case of carbon-15, it has 6 protons and 9 neutrons. This configuration leads to a ratio of neutrons to protons that is too high, making the nucleus unstable. To achieve a more stable state, carbon-15 transforms one of its neutrons into a proton through a radioactive process known as beta decay. During this process, the unstable neutron emits a beta particle (which is essentially an electron) and an antineutrino, leading to a change in the atomic structure.
Once the beta decay occurs, carbon-15 transforms into nitrogen-15, which has 7 protons and 8 neutrons, achieving a more stable neutron-to-proton ratio. This adjustment is nature’s way of seeking stability, as stable isotopes generally have a balanced ratio of protons to neutrons, reducing the likelihood of further decay.