Nucleons are composite particles made up of protons and neutrons. The protons and neutrons collectively present in the nucleus of an atom are called nucleons.The nucleons occupy very small space inside the nucleus. Nucleons are an important part of an atomic nucleus and therefore, they are important in particle physics.Every mass in the matter is made up of atoms and molecules, and atoms are in turn compose of nucleons.ucleons are an important part of an atomic nucleus and therefore, they are important in particle physics. Every mass in the matter is made up of atoms and molecules, and atoms are in turn compose of nucleons.