Chemistry

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Across
  1. 1. number of electrons
  2. 3. Bohr model of atom
  3. 5. neutral particles
  4. 8. discovered the electron
  5. 10. Chemical reaction is a rearrangement of atoms
  6. 11. negatively charged protons
  7. 12. discovered first neutron
Down
  1. 2. Positively charged particles
  2. 4. number of electron shells
  3. 6. gold foil experiment
  4. 7. Unit of a Chemical Element
  5. 9. substance consisting of atoms which have the same number of protons