Nuclear Energy

1. the total number of protons and neutrons in a nucleus.
3. the time taken for the radioactivity of a specified isotope to fall to half its original value
5. a fast-moving electron emitted by radioactive decay of substances.
7. same element that contain equal numbers of protons but different numbers of neutrons in their nuclei, and hence differ in relative atomic mass but not in chemical properties; in particular, a radioactive form of an element.
8. a chemical reaction or other process in which the products themselves promote or spread the reaction, which under certain conditions may accelerate dramatically.
12. emitting or relating to the emission of ionizing radiation or particles
13. a subatomic particle of about the same mass as a proton but without an electric charge, present in all atomic nuclei except those of ordinary hydrogen.
14. a nuclear reaction where a heavy nucleus splits on impact with another particle

2. a helium nucleus emitted by some radioactive substances, originally regarded as a ray.
4. gamma rays
6. the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table.
9. a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.
10. the positively charged central core of an atom, consisting of protons and neutrons and containing nearly all its mass
11. a stable subatomic particle occurring in all atomic nuclei, with a positive electric charge equal in magnitude to that of an electron, but of opposite sign.