Physics

2. The rows in the periodic table.
7. The regions in which electrons move rapidly around the nucleus.
8. Energy-releasing reactions.
11. An ion made up of more than one atom that acts as a single particle.
15. A bond that usually results from the sharing of outer electrons between non-metal atoms.
16. A negatively charged ion

1. The columns in the periodic table.
3. A positively charged ion.
4. A group of two or more atoms joined by chemical bonds.
5. A reaction in which a large or more complex molecule breaks down to form two or more simpler products.
6. A substance that dissolves in water to produce a solution that conducts electricity.
8. Atoms must have an equal number of protons and ________
9. The outer shell of an atom.
10. Substances formed in a reaction.
12. Compounds that contain two different elements.
13. The central part of an atom which is made up of protons and neutrons and contains most of the mass of the atom
14. A tiny, positively charged particle found in the nucleus of an atom.