The 100 or so elements are listed by #Z_"the atomic number"#. #"Z=1, hydrogen; Z=2, helium; Z=3, lithium; …..Z=92, uranium.."#
And by definition, #Z# represents the number of MASSIVE, POSITIVELY charged particles, i.e. nuclear protons, that are present in the element's nucleus, and #Z# thus defines the IDENTITY of the given nucleus. Also present in the nucleus are neutrons, massive particles of ZERO charge, and interactions between protons and neutrons at these infinitesimally small nuclear ranges comprise the strong nuclear force, which is strong enuff to overcome the electrostatic force of REPULSION between the like-charged protons.
And around in the nucleus in the NEUTRAL atom, a number of electrons equal to #Z# whizz about, and sharing and transfer of electrons results in all of chemistry.