#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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