The Shell Model is a theoretical framework used in nuclear physics to describe the structure of atomic nuclei. It suggests that protons and neutrons, the building blocks of nuclei, occupy specific energy levels or "shells," similar to how electrons are arranged around an atom. This model helps explain the stability and behavior of different isotopes. In the Shell Model, each shell can hold a certain number of nucleons, and the arrangement of these nucleons influences the nucleus's properties. The model accounts for phenomena such as nuclear magic numbers, which are specific numbers of nucleons that result in particularly stable nuclei, like those of Helium or Lead.