What is a nucleon in chemistry


As Nucleons [nukleˈoːnən] (singular Nucleon [ˈNuːkleɔn]; lat.nucleus "The nucleus") is the name given to the atomic nucleus building blocks, i.e. the particles that make up atomic nuclei, namely protons and neutrons.

Nucleons are all baryons that are composed exclusively of the light up and down quarks and have the isospin 1/2. In addition to protons and neutrons, this definition also includes excited states with the quark composition (uud) and (udd), the extremely short-lived nucleon resonances. The Particle Data Group sees the existence of 14 nucleons as certain (evidence is certain) or as good as secured (evidence ranges from very likely to certain) and has evidence of a further eight nucleons (as of 2007). The charge states are not differentiated here; With this counting method, proton and neutron are one and the same nucleon.

The quarks have only 5% of the mass of the nucleons, the remaining 95% originate from the binding energy and the kinetic energy of the quarks.[1][2] A research team at Forschungszentrum Jülich succeeded in calculating the mass of protons and neutrons theoretically. The simulations confirm the fundamentals of quantum chromodynamics.

Individual evidence

  1. ↑ Supercomputers calculate the exact nucleon mass for the first time
  2. ↑ Science Nov. 21, 2008, Vol. 322, 5905

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