The Periodic Table

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Across
  1. 1. the total number of protons and neutrons in the nucleus of an atom
  2. 4. an atom or groups of atoms that lose or gain electrons
  3. 7. an electron in the outermost energy level of an atom
  4. 9. another name for a period
  5. 10. a horizontal row of elements in the periodic table
Down
  1. 2. the number of protons in the nucleus of an atom
  2. 3. any of the possible energies an electron may have in an atom
  3. 5. the center of an atom; made up of protons and neutrons
  4. 6. any atoms having the same number of protons but a different number of neutrons
  5. 8. a region in an atom where there is a high probability of finding electrons