Such a series is called a radioactive series. C. Stability of Atomic Nuclei 1. Neutrons moderate the repulsive forces between the protons. Magic numbers-nuclear shells are filled by protons or neutrons. Any combination of nucleons which gives these numbers provides a more stable isotope.
Isotopes containing both a magic number of protons and neutrons are especially stable.
Unstable isotopes will often change in such a way as to become like one of the stable isotopes. Binding Energy-the energy released when a nucleus is formed from its constituent parts. D. Half-Life and Radiochemical Dating 1. Radioisotopes decay at a constant rate which can be determined experimentally. The unit of measure is disintegrations per time.