#atom  (physics and chemistry) the smallest component of an element having the chemical properties of the element
  supertype:  substance__matter  that which has mass and occupies space; "an atom is the smallest indivisible unit of matter"
  subtype:  ion  isotope  monad  carbon_atom  hydrogen_atom  free_radical
  part of:  chemical_element  molecule
  part:  elementary_particle__fundamental_particle__fundamentalparticle__subatomicparticle  a particle that is less complex than an atom; regarded as constituents of all matter
  part:  nucleus__nucleu  the positively charged dense center of an atom
     part:  nucleon  a constituent (proton or neutron) of an atomic nucleus

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