What particle in an atom has a positive charge?

The particle in an atom that has a positive charge is the proton. It carries one elementary unit of positive electric charge, written as +1e, and is found in the atom’s nucleus alongside neutrons.

Protons are baryons made of three quarks: two up quarks and one down quark. The strong nuclear force, carried by gluons, binds these quarks together. A proton is much heavier than an electron—about 1,836 times as massive—although its charge is equal in size and opposite in sign to the electron’s.

The number of protons identifies an element. Hydrogen has one proton, helium has two, and carbon has six. If an atom gains or loses electrons, it becomes an ion, but its identity does not change. A common mix-up is confusing protons with neutrons: neutrons are electrically neutral, while electrons carry negative charge.