Electric Crossword

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Across
  1. 3. positively charged particles
  2. 5. negatively charged particles
  3. 6. the flow of electrons
  4. 7. materials that don't allow electrons to flow through them
Down
  1. 1. checks the amount of power in a battery
  2. 2. materials that allow electrons to flow through them
  3. 4. smaller than an atom