A proton is a subatomic particle found in the nucleus of an atom. It carries a positive electric charge and has a mass that is approximately 1,836 times that of an electron. Protons, along with neutrons, make up the atomic nucleus, which is the central part of an atom. The number of protons in an atom determines its atomic number and defines the element, such as hydrogen or oxygen. Protons are essential for the stability of atoms and play a crucial role in chemical reactions. They interact with electrons and other particles through fundamental forces, including the strong nuclear force, which holds the nucleus together. Understanding protons is vital in fields like chemistry and physics, as they are key to the structure of matter and the behavior of elements in the periodic table.