Protonstypically

Protonstypically is not a standard term in physics; this article uses protons and their typical properties to describe the concept. Protons are positively charged subatomic particles that reside in atomic nuclei. They are baryons composed of three valence quarks—two up quarks and one down quark—bound by gluons, within the framework of quantum chromodynamics. The proton carries a unit positive electric charge and has a rest mass of about 1.6726×10^-27 kg (approximately 938 MeV/c^2). Its charge radius is about 0.84–0.87 femtometers.

Within the Standard Model, protons are not fundamental; they are composite particles with internal dynamics. The three valence quarks, along with sea quarks and gluons, contribute to properties such as spin (1/2) and magnetic moment. The strong force, mediated by gluons, binds quarks together; color confinement prevents isolated quarks from existing freely.

In atoms, the number of protons defines the atomic number Z, which identifies the element and governs chemical behavior via electrons arranged around the nucleus. Protons and neutrons make up the nucleus; the balance of protons and neutrons determines nuclear stability and binding energy. The electrostatic repulsion between protons is offset by the strong nuclear force.

Protons occur naturally in hydrogen and in most elements. They are produced in stars by fusion and in cosmic-ray interactions. Free protons are extremely long-lived; experiments place a lower bound on the proton lifetime around 10^34 years, with no observed decay. In stars, protons participate in fusion chains such as the proton–proton cycle; in laboratories they serve as probes of matter.