Periodic Puzzle

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Across
  1. 2. We're never 100% sure where it is located
  2. 4. Shiny mix of iron and sulfur (2 words)
  3. 6. This has the highest atomic number of all the naturally occurring elements
  4. 12. Don't eat this unless you really like garlic (and poison)
  5. 13. Mom's bday number element
  6. 14. The gas in between the panes of glass in most double pane windows
  7. 15. Used (and reused) in modern computer screens
Down
  1. 1. Positively charged particle
  2. 3. The most expensive element you can buy
  3. 5. An element that makes a green flame when burned
  4. 7. Used in steel to make tough cannons & guns in World War I
  5. 8. Used to be in hats, creating Mad Hatter's Disease
  6. 9. A yellow gas that can make bricks catch fire
  7. 10. Least reactive element
  8. 11. Glows dark blue when electrified inside a tube