Protons are located inside the nucleus of an atom. The nucleus is the central region of an atom that contains positively charged protons and uncharged neutrons. The number of protons in the nucleus determines the atomic number and identifies the element. For example, an atom with one proton is hydrogen, while an atom with six protons is carbon. The protons inside the nucleus are held together by the strong nuclear force, which is much stronger than the electrostatic repulsion between positively charged particles.