Periodic Cross

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Across
  1. 4. I am the most electro-negative element
  2. 6. My chemical symbol is W
  3. 8. I am the cation in table salt
  4. 9. I have one electron
  5. 12. I am the Halogen in Period 5
  6. 13. I am the Noble gas in Period 5
  7. 14. I am the only transition metal that is liquid at room temperature
  8. 16. I make up the majority of Earth's atmosphere
Down
  1. 1. I am associated with the smell of rotten eggs
  2. 2. I am used to fill up balloons
  3. 3. I am found in milk, bones, and chalk
  4. 5. I am named after a famous physicist
  5. 7. I have 79 protons
  6. 10. I have an atomic weight of about 16
  7. 11. I am the lightest transition metal
  8. 15. All organic compounds contain me