George's Periodic Table Crossword Puzzle

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Across
  1. 1. I'm industrially produced by cryogenically distilling air.
  2. 4. Animals, and plants require this.
  3. 8. I'm the most reflective material.
  4. 9. Compared to other metals, I'm less chemically reactive.
  5. 10. I'm a bluish-white metal that is hard, but brittle.
  6. 13. It's a pure black amorphous powder.
  7. 16. The heaviest metal.
  8. 18. Is a soft white metal named after Europe.
  9. 19. My atomic symbol Dy,
  10. 20. Has an atomic number of 10.
Down
  1. 2. The air we breathe is 78% percent of this
  2. 3. The second most abundant element in the universe
  3. 5. My atomic number is 54.
  4. 6. The lightest metal
  5. 7. Around 10% of the mass in the human body is made of me.
  6. 11. Has the same name as a planet.
  7. 12. This metal is known as "white gold".
  8. 14. Has an atomic symbol of Ra.
  9. 15. Can take the form of one of the hardest substances or one of the softest.
  10. 17. We get most of this from milk.