Nuclear Radioactivity

3. radioactive material left over from the operation of nuclear reactors
4. time takes for half of a given quantity of substance to decay
6. basic unit of chemical element/building block
8. by which an unstable atomic nucleus trans into more stable
11. extremely dense and tiny,central core of atom contain almost all of its mass
12. where 2 light atomic nuclei combine to form single
13. large atomic nucleus splits into 2 or more

1. energy as electromagnetic waves or as moving subatomic particles
2. energy released from an atoms nucleus which is central core
5. with unstable atomic nuclei that decay to become stable
7. sequence of reactions where a reactive product or by-product causes additional reactions
9. two or more forms of of same element that contains equal number of protons but different number of nuetrons
10. central membrane bound organelle