The proton's a subatomic particle with an electric charge of +1 elementary charge. It's found in the nucleus of each atom but's also stable by itself and has a second identity as the hydrogen ion, 1H+. It's composed of 3 even more fundamental particles comprising two up quarks and one down quark. Description Protons are spin-1/2 fermions and are composed of three quarks, making them baryons. The two up quarks and one down quark of the proton are held together by the strong force, mediated by gl… (More on Proton)