Across
- 4. Something that causes a bunch of reactions to continue on
- 6. The average number of all known isotopes of an element
- 9. A neutron hits a nucleus, the nucleus releases 3 neutrons; causes a chain reaction
- 10. 2 nuclei combine to make another atom
- 12. No mass, one proton changes
- 14. A version of the same element that has a different number of neutrons
Down
- 1. A powerful form of energy; stopped by lead
- 2. An element's assigned number on the periodic table
- 3. The ability to omit energy and mass
- 5. A subatomic particle with no charge
- 7. The center of an atom, made of protons and neutrons
- 8. The time it takes for something to decay by half
- 11. 2 protons, 2 neutrons, helium.
- 13. A subatomic particle with a positive charge