A neutron is a subatomic particle that resides within the atomic nucleus alongside protons. Distinguished by its lack of net electric charge, it is electrically neutral, meaning it neither gains nor loses an electrical charge. These particles contribute significantly to the stability and mass of atoms. The presence of neutrons dictates the behavior of the nucleus in various physical processes, most notably in nuclear reactions such as fission and fusion. The interactions involving these particles are fundamental to the understanding of matter and energy transformation at the atomic level.