Atoms and the Periodic Table

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1234567891011121314151617181920
Across
  1. 1. symbol is "Ar"
  2. 3. second element in column 16
  3. 9. atomic mass is 20.180
  4. 10. atomic number 5
  5. 11. atomic mass of 9.0122
  6. 13. atomic number 19
  7. 15. symbol is "O"
  8. 16. atomic number 1
  9. 17. first element in column 14
  10. 18. starts with "so" and ends in "dium"
  11. 19. has 20 protons
Down
  1. 2. 7 protons
  2. 4. has 3 protons
  3. 5. atomic number 9
  4. 6. atomic number 15
  5. 7. atomic number 14
  6. 8. symbol is "He"
  7. 12. atomic number 12
  8. 14. atomic number 17
  9. 20. atomic mass of 26.982