Chemistry

12345678910111213
Across
  1. 1. Major player in the creation of DNA
  2. 3. Used to blow up balloons
  3. 6. Third noble gas in period 8
  4. 8. I am to the left of the periodic table
  5. 9. I contain 26 protons
  6. 11. Green plastids
  7. 12. Makes up 21% of the air
  8. 13. Atomic number is 92
Down
  1. 2. Usually used in pools
  2. 4. Lightest state of matter
  3. 5. Metal that turns liquid at room temperature
  4. 7. I take up 80% if the atmosphere
  5. 10. Poisonous Gaseous halogen