Periodic Puzzle

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Across
  1. 3. Symbol is "Fe", used to make steel
  2. 5. Found in table salt, symbol is "Na"
  3. 6. The gas we need to breathe
  4. 9. This noble gas makes balloons float
  5. 10. Found in pencils, symbol is "C"
Down
  1. 1. Symbol is "K", important for muscles
  2. 2. A liquid metal at room temperature
  3. 4. The lightest element
  4. 7. A yellow metal, very valuable
  5. 8. A gas used in lights, symbol is "Ne"