Periodic table

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Across
  1. 3. A noble gas that makes up about 1% of the air.
  2. 5. Found in Epsom salts and chlorophyll.
  3. 8. Makes up 78% of Earth's atmosphere.
  4. 9. The second lightest element; used in balloons.
  5. 10. The basis of all known life on Earth.
  6. 11. A yellow non-metal known for its "rotten egg" smell.
  7. 13. A highly reactive metal stored in oil.
  8. 16. The lightest metal; used in batteries.
  9. 17. Essential for breathing and combustion.
  10. 18. Used in computer chips and glass.
  11. 19. Essential for strong bones and teeth.
Down
  1. 1. The lightest metalloid; used in Pyrex glass.
  2. 2. A lightweight metal used in aerospace alloys.
  3. 4. Found in matches and DNA; glows in the dark.
  4. 6. A noble gas used in colorful advertising signs.
  5. 7. Often found in bananas; helps nerve function.
  6. 9. The most abundant element in the universe.
  7. 12. Found in toothpaste to prevent cavities.
  8. 14. A lightweight metal used in soda cans.
  9. 15. A halogen used to keep swimming pools clean.