Atoms and Elements Crossword Puzzle

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Across
  1. 4. the mass of the protons and neutrons in an atom
  2. 8. negatively charged particles
Down
  1. 1. substances that cannot be broken down into simpler substances by chemical means
  2. 2. positively charged particles
  3. 3. a unique number that indicates the number of protons in an element's nucleus
  4. 5. all matter is made of tiny particles called ______
  5. 6. these letters are abbreviations that represent the name of the element (example Fe represents iron)
  6. 7. particles with no charge