Protons are spin-1/2 fermions and are composed of three valence quarks, making them baryons
Protons … See more

The concept of a hydrogen-like particle as a constituent of other atoms was developed over a long period. As early as 1815, William Prout proposed that all atoms are composed of hydrogen atoms (which he called "prot… See more

One or more bound protons are present in the nucleus of every atom. Free protons are found naturally in a number of situations in which energies or temperatures are high enough to separate them from electrons, for which they … See more

The spontaneous decay of free protons has never been observed, and protons are therefore considered stable particles according to the Standard Model. However, some grand unified theories (GUTs) of particle phy… See more

In quantum chromodynamics, the modern theory of the nuclear force, most of the mass of protons and neutrons is explained by special relativity. The mass of a proton is about 80–100 times greater than the sum of the rest ma… See more