Atomic

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Across
  1. 3. a particle smaller than an atom
  2. 5. have a charge of +1
  3. 7. discovery of atoms
  4. 8. symbol e^-
  5. 9. a particle with no electric charge
Down
  1. 1. the basic unit of a chemical element
  2. 2. number every oxygen atom has 8 protons
  3. 4. a proton and a neutron have a mass equal to about one amu.
  4. 6. containing protons and neutrons
  5. 7. region of moving electrons