Science

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Across
  1. 4. electron in the outermost shell
  2. 8. neither metals nor non-metals
  3. 10. the bonding between ions
  4. 11. short name of this element is O
  5. 12. center of our solar system
Down
  1. 1. covers most of earth's surface
  2. 2. positively charged ion
  3. 3. not a planet anymore :(
  4. 5. the bonding between two non-metals
  5. 6. average mass of an atom
  6. 7. isn't in the nucleus, but in shells around
  7. 9. negatively charged ion