Proton

The proton is a particle of one unit positive electric charge. The nucleus of the hydrogen atom, H⁺, is a single proton. The nuclei of other atoms are composed of neutrons and protons held together by the strong nuclear force. The number of protons in the nucleus determines the chemical properties of the atom and what chemical element it is.

A proton has a mass of 1.6726231 * 10^-27 kg, which is about 1800 times as heavy as an electron.

Protons are classified as baryons and are composed of two up quarks and one down quark, which are also held together by the strong nuclear force.

See also particle physics, chemistry, proton decay