Across
- 2. smallest part of an element
- 5. negative charge
- 6. smallest part of an atom
- 7. its relative mass number
- 9. pure substance
- 11. a chemical bond of elements
- 12. positive charge
Down
- 1. an impure substance
- 3. impure substance
- 4. neutral charge
- 6. number of protons and neutrons
- 8. amount of protons
- 10. a thing with only one type of atom