nukleonernas

Nukleonernas is the Swedish term for the nucleons—the protons and neutrons that make up atomic nuclei. In physics, nucleons are baryons composed of three quarks: the proton with quark content up-up-down (uud) and the neutron with down-up-down (udd). They have spin 1/2 and carry baryon number 1; the proton has electric charge +1e, while the neutron is electrically neutral. Their masses are approximately 938 MeV/c^2 for the proton and 939 MeV/c^2 for the neutron.

In atomic nuclei, nucleons are bound together by the strong nuclear force, mediated by mesons, within arrangements shaped by quantum effects and electromagnetic repulsion among protons. The number of nucleons (A) and the number of protons (Z) define a nucleus’s identity as an isotope, with binding energy determining its stability. The binding energy per nucleon generally rises toward iron-56 and then slowly decreases for heavier nuclei.

Nucleon properties and interactions are described at different levels. Quantum chromodynamics (QCD) governs their substructure in terms of quarks and gluons, while effective models—such as the nuclear shell model and the liquid drop model—describe many bulk nuclear properties. Nucleon–nucleon interactions are modeled with potentials and meson exchange; pion exchange has historical significance in explaining the range of the nuclear force.

Nucleons are central to a wide range of phenomena, from nuclear reactions and energy production in stars to applications in medicine and industry.