Periodic table

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Across
  1. 4. Gives a brick red flame
  2. 6. Noble gas with a duplet
  3. 8. A monovalent nonmetal
  4. 9. Radioactive elements
  5. 10. Supporter of combustion
Down
  1. 1. A highly reactive metal
  2. 2. A metalloid in Period 3
  3. 3. A neutral gas
  4. 4. Metal with variable valency 1 and 2
  5. 5. Electrons in the outermost orbit
  6. 7. Valency of Group 18 elements