Periodic table elements puzzle

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Across
  1. 3. For formation of bones and teeth
  2. 7. Atomic number is 9
  3. 8. Symbol is Al
  4. 11. flammable gas
  5. 12. Used in lamps and signs
  6. 15. something that is important in body functions
  7. 16. Used to make glue
  8. 18. number of 4
Down
  1. 1. Has an atomic number of six
  2. 2. What some pools have
  3. 4. Atomic number of 16
  4. 5. Has 2,3 electrons per shell
  5. 6. Makes up 78 percent of the earths atmosphere
  6. 8. symbol is Ar
  7. 9. Has 2 valence electrons
  8. 10. What salt is composed of
  9. 11. what we put in balloons so they can go up
  10. 13. Milk has this
  11. 14. a soft silver white metal
  12. 17. What we breathe