Atoms and radioactivity

3. made up of one or more atoms
4. energy, in the form of particles or electromagnetic rays, released from radioactive atoms.
8. a substance made from two or more different elements that have been chemically joined.
10. bound an attraction between two or more atoms that form a chemical.
11. a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.
12. the transmutation of a neutron into a proton and an electron
16. radiation consisting of alpha particles.
17. atomic nuclei, with a positive electric charge
19. The smallest part of a substance that cannot be broken down chemically.
20. The splitting of an unstable atomic nucleus into two or more nuclei.

1. a stable subatomic particle with a charge of negative electricity
2. the time required for half of something to undergo a process:
5. The central and most important part of an object.
6. a radioactive isotope.
7. a pure substance made of only 1 type of atom
9. the emission of energy in the form of ionizing radiation
13. a form of electromagnetic radiation
14. A table of the chemical elements arranged in order of atomic number.
15. each of two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei.
18. same mass as a proton but without an electric charge