Across
- 3. the fuel for fusion reactions
- 4. a particle emitted that is identical to a helium nucleus
- 6. splitting of a heavy nucleus
- 7. the time it takes for half the mass of a radioactive isotope to decay
- 13. the changing into another element by radioactive decay
- 17. large nuclei need a neutron to _ ratio of over 1:1 to be stable
- 18. particle emitted when neutron changes into a proton in the nucleus
- 21. fusion reactions only occur at extremely high _
- 22. this type of nuclei, with mass numbers over 82, are always unstable
- 23. the nucleus makes up almost all of the _ of an atom
- 24. atoms of the same element with different masses
Down
- 1. man-made elements are produced by the _ of an isotope with nuclear "bullets"
- 2. reaction occurring when neutrons produced in fission reactions strike other nuclei
- 5. minimum mass required for chain fission reactions is _ mass
- 8. the combination of two nuclei into one
- 9. unstable nuclei are
- 10. A nuclear _ controls fission chain reactions to produce useable energy
- 11. emission with no change of mass or charge
- 12. the force of attraction between nearest neighbor nucleons
- 14. fusion naturally occurs on the:
- 15. protons and neutrons
- 16. nuclear bullets used in fission reactions
- 19. One danger of nuclear reactors is the breakdown of cooling systems, allowing this
- 20. when electrical _ between protons is greater than strong forces, the nucleus will be unstable