Across
- 4. atom with different mass than average
- 5. positive charge
- 7. the amount of protons
- 12. Happens in nuclear fission
- 14. an electron
Down
- 1. spontaneous disintegration of atomic nuclei
- 2. Fuse together
- 3. A part of an atom with no charge
- 6. Center of the atom
- 8. the weight of an atom
- 9. helium particle
- 10. the time taken for the radioactivity of a specified isotope to fall to half its original value
- 11. Chain reaction
- 13. a radioactive energy