Periodic Table Crossword

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Across
  1. 2. quantity equal to one-twelfth of a carbon-12 atom
  2. 3. number of protons in an element
  3. 6. reactive group 1 elements
  4. 9. unreactive group 18 elements
  5. 10. elements that are not good conductors of heat and electricity
  6. 11. average weight of all natural occurring isotopes of an atom
  7. 16. vertical column of elements on the periodic table
  8. 18. semi-conducter used in computers
Down
  1. 1. states that properties of elements change in a predictable way when arranged by atomic number
  2. 2. reactive group 2 elements
  3. 4. reactive group 17 elements
  4. 5. metallic elements in groups 3-12
  5. 7. elements in the break in period 6
  6. 8. the heaviest noble gas
  7. 11. elements in the break in period 7
  8. 12. horizontal row of elements on the periodic table
  9. 13. number of protons and neutrons in an atom
  10. 14. elements that are intermediate conductors of heat and electricity
  11. 15. lightest noble gas
  12. 17. elements that are good conductors of heat and electricity