The Proton is an elementary particle with high mass and an elementrary positive charge. The mass is the same like the mass of the electrical neutral neutrons and together with those it forms the atomic nucleus. In case of hydrogen the nucleus is just one proton. In general the numbers of protons and neutrons in a nucleus of a lightweight atom are identical. In a neutral atom the number of protons in the atomic nucleus is identical to the number of electrons in the atomic shell.