Across
- 3. electromagnetic wave
- 5. Atomic weight
- 6. different atomic mass
- 8. electricity
- 10. stars
- 12. cause and effect
- 13. nuclear charge number
- 14. the time taken for something to halve its quantity
Down
- 1. atom-chipping
- 2. negative electric charge
- 4. helium-4
- 7. positive
- 9. core
- 11. neutral