Chemistry

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Across
  1. 3. - Hint: Substance composed of two or more elements.
  2. 4. - Hint: Equals the number of protons in an atom's nucleus.
  3. 5. - Hint: Attraction force that holds atoms together in molecules.
  4. 7. - Hint: Substance that speeds up a chemical reaction.
Down
  1. 1. - Hint: Having a pH value below 7.
  2. 2. - Hint: Path followed by electrons around the nucleus.
  3. 6. - Hint: Center of an atom.
  4. 8. - Hint: Basic unit of a chemical element.