Chemistry

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Across
  1. 2. The number of protons and neutrons contained in the atom
  2. 5. The burning of a substance in oxygen is an example of ...
  3. 7. 31 on the periodic table
  4. 8. The most electronegative element
  5. 9. A bunch of different atoms bonded together
Down
  1. 1. Smallest known particle
  2. 3. Metal+Oxygen=
  3. 4. Combustion is an ... reaction
  4. 6. The number of protons contained in an atom