Across
- 1. Hulk
- 3. two or more atomic nuclei are combined
- 6. first letter of the greek alphabet
- 9. splitting or breaking up into parts
- 10. a radioactive isotope
- 11. present in all atomic nuclei
- 13. has a positive electric charge
Down
- 2. number of a chemical elements
- 4. he act of emitting radiation spontaneously
- 5. half of life of an nuclei
- 7. total number of neutrons and protons
- 8. the second star in a constellation
- 12. some elements have only one stable______