Periodic Table Crossword Puzzle

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Across
  1. 4. repeats at regular intervals
  2. 6. dull, brittle elements that are poor conductors
  3. 7. nonmetal that is liquid at STP in Group 17
  4. 9. size of an ion
  5. 11. metalloid in period 2
  6. 14. vertical columns on the periodic table
  7. 15. this element has the symbol Li
  8. 18. lustrous, malleable elements that are good conductors
  9. 20. having the same number of electrons or the same electron configuration
Down
  1. 1. most reactive nonmetal
  2. 2. consisting of two atoms
  3. 3. measure of attraction of a nucleus in bonded electrons
  4. 5. most metals on the periodic table are __________ metals
  5. 8. horizontal rows on the periodic table
  6. 10. only element in group 6 with three oxidation states
  7. 12. size of a neutral atom
  8. 13. element with an atomic mass of 40.08
  9. 16. metal that is liquid at STP in Group 12
  10. 17. element with an atomic number of one
  11. 19. have properties of metals and nonmetals