Chemical Puzzle

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Across
  1. 4. cloud outer layers of atoms
  2. 5. center of the atoms
  3. 7. solid made from 2 liquids
  4. 9. dangerous substance to your health
  5. 10. ability to burn or ignite
Down
  1. 1. two or more atoms bonded together
  2. 2. make up all the matter in the universe
  3. 3. ability to react with other elements
  4. 6. light or heat
  5. 7. substances you end with after the chemical reaction
  6. 8. substances you start with before the chemical reaction