Properties Nucleon

protons , neutrons important , best known constituting atomic nuclei, can found on own, not part of larger nucleus. proton on own nucleus of hydrogen-1 atom (h). neutron on own unstable (see below), can found in nuclear reactions (see neutron radiation) , used in scientific analysis (see neutron scattering).

both proton , neutron made of 3 quarks. proton made of 2 quarks , 1 down quark, while neutron 1 quark , 2 down quarks. quarks held strong force, or equivalently, gluons, mediate strong force.

an quark has electric charge + ⁄3 e, , down quark has charge − ⁄3 e, total electric charge of proton , neutron +e , 0, respectively. word neutron comes fact electrically neutral .

the mass of proton , neutron quite similar: proton 6973167260000000000♠1.6726×10 kg or 7002938270000000000♠938.27 mev/c, while neutron 6973167490000000000♠1.6749×10 kg or 7002939570000000000♠939.57 mev/c. neutron 0.1% heavier. similarity in mass can explained slight difference in mass of quark , down quark composing nucleons. however, detailed explanation remains unsolved problem in particle physics.

the spin of both protons , neutrons  ⁄2. means fermions not bosons, , therefore, electrons, subject pauli exclusion principle. important fact in nuclear physics: protons , neutrons in atomic nucleus cannot in same quantum state, instead spread out nuclear shells analogous electron shells in chemistry. reason spin of proton , neutron important because source of nuclear spin in larger nuclei. nuclear spin best known crucial role in nmr/mri technique chemistry , biochemistry analysis.

the magnetic moment of proton, denoted μp, 7000279000000000000♠2.79 nuclear magnetons (μn), while magnetic moment of neutron μn = 2999809000000000000♠−1.91 μn. these parameters important in nmr/mri.