Periodic Table

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Across
  1. 5. People used to put me on top of hats.
  2. 7. I have the atomic number of 20.
  3. 8. I am a precious metal that is extremely valuable.
  4. 10. Steel wool burns when exposed to me.
  5. 11. I have an atomic mass of 47.90.
  6. 12. I am part of the Alkali family and I am never found in nature.
  7. 15. My atomic mass is 83.80.
  8. 17. Jupiter's moon Io owes its colors to various forms of me.
  9. 18. I am a gas that is used in neon signs to create the color orange.
  10. 19. I am found in most meteorites and a coin in America is named after me.
Down
  1. 1. When I react with aluminum, a purple gas is produced.
  2. 2. I am extremely flammable and and I am used to create balloon structures.
  3. 3. I am the most common element in the universe.
  4. 4. When I am freshly exposed to air, I exhibits a metallic lustre.
  5. 6. I am located in group 2 and I have a high boiling point.
  6. 9. I am the most common element in the atmosphere.
  7. 13. I am used to make fireworks.
  8. 14. I am the only metalloid in the Boron family.
  9. 16. I am essential for life on Earth.
  10. 20. I am located in the Carbon family and I have a low melting point.