#nucleon  a constituent (proton or neutron) of an atomic nucleus
  supertype:  baryon__heavy_particle__heavyparticle  any of the elementary particles having a mass equal to or greater than that of a proton and that participate in strong interactions; a hadron with a baryon number of +1
  part of:  nucleus
  subtype:  antineutron  the antiparticle of a neutron
  subtype:  antiproton  an unstable negatively charged proton; the antiparticle of a proton
  subtype:  neutron  an elementary particle with 0 charge and mass about equal to a proton; enters into the structure of the atomic nucleus
  subtype:  proton  a stable particle with positive charge equal to the negative charge of an electron
     subtype:  hydrogen_ion  a positively charged atom of hydrogen; that is to say, a normal hydrogen atomic nucleus

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