Periodic Table Crossword

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Across
  1. 4. A grey, brittle alkaline earth metal with valency 2
  2. 7. a diatomic molecule, with a valency of 1
  3. 9. highest melting point, can be found mainly in 2 forms with a valency of 4.
  4. 12. colourless and odourless gas, 21% of it is in the air
  5. 13. Non-metal with atomic size 188pm and valency 0
  6. 14. A yellow-green gas at room temperature
  7. 16. A tasteless yellow solid with the 4th highest metallic character
  8. 18. The most widely used non ferrous metal
  9. 21. A noble gas used for filling balloons and dirigibles
Down
  1. 1. Element present in glass and used as a semiconductor
  2. 2. I appear in as the last number in an electronic configuration
  3. 3. Most reactive non metal
  4. 5. Element of low metallic character in group 15, makes up 1% of a persons total body weight
  5. 6. Metal with valency 1 has a Latin name Kalium
  6. 8. Inert Gas used for lighting
  7. 10. a silvery white material, also found in our bones and teeth
  8. 11. A silvery white element with valency 2 that is highly resistant to corrosion
  9. 15. The highest purity of which exists as an amorphous dark brown to black powder
  10. 17. Period 3 metalloid
  11. 19. Element with high metallic character belonging from the 1st group and second period
  12. 20. Metal with atomic size 227pm has the Latin name Natrium