Periodic table

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Across
  1. 3. Group of highly reactive metals (number)
  2. 5. 53 protons
  3. 9. Diamonds, charcoal, graphite
  4. 10. Symbol Na
  5. 12. Largest naturally occurring element
  6. 13. Readily forms a positive ion with 18 electrons
  7. 16. 52 electrons
  8. 17. Metalloid used for computer chips
  9. 21. Easily oxidized
  10. 22. Hindenburg fuel
  11. 24. Catalytic convertor metal
  12. 25. Russian inventor of periodic table, Dmitri
  13. 26. Heavy, malleable metal
  14. 27. Symbol Zn
Down
  1. 1. Valuable yellow metal
  2. 2. Noble gas used for colored illumination
  3. 4. The number of the group of unreactive gases
  4. 6. 5 protons 5 electrons
  5. 7. Superman
  6. 8. Vertical rows on the periodic table
  7. 11. Toxic liquid metal, same name as planet
  8. 14. High-pitched
  9. 15. Most electronegative element
  10. 18. Wires (conductive metal)
  11. 19. Atomic number of Mg
  12. 20. Horizontal rows of the periodic table
  13. 23. Breath