Chemistry crossword

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Across
  1. 3. the oldest known pills
  2. 6. so dangerous the 19th century experimenter were deemed
  3. 7. wide spread occurrence in earths crust
  4. 10. one of the first mental to be used by humans
  5. 11. highest electrical conductivity
  6. 12. main component of teeth and bones
  7. 14. for ly used in self luminous paints for watches
  8. 15. few elements that is liquid
Down
  1. 1. it is the first most abundant chemical
  2. 2. found on the sun before earth
  3. 4. blood is red
  4. 5. second most abundant element in the human body
  5. 8. 24.305u
  6. 9. table salt
  7. 12. first metal to be worked by men
  8. 13. first used as a weapon in World War One