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  • Word comparison: atomic number vs. mass number

atomic number vs. mass number

atomic number

noun

  1. the number of positive charges or protons in the nucleus of an atom of a given element, and therefore also the number of electrons normally surrounding the nucleus. : at. no.; : Z

mass number

noun

Physics.
  1. the integer nearest in value to the atomic weight of an atom and equal to the number of nucleons in the nucleus of the atom. : A