| A | B |
|---|
| atom | the smallest part of an element that is still that element |
| proton | a positively charged atomic particle |
| electron | a negatively charged atomic particle |
| neutron | a neutral atomic particle |
| positive charge | opposite of negative charge; the kind of charge on a proton |
| negative charge | opposite of positive charge; the kind of charge on a proton |
| neutral | neither positively nor negatively charged |
| nucleus | the center of an atom |
| orbit | a path that electrons follow around the nucleus |
| atomic mass unit (A.M.U.) | a unit used for the weight of atoms; the weight of one proton |
| atomic weight | the weight of an atom's protons and neutrons |
| electron shell | all of an electron's orbits, or paths, put together |
| electrovalent compound | a compound formed when atoms lend and borrow electrons |
| ion | a charged atom |
| covalent compound | a compound in which atoms share electrons |
| oxidation number | the number of electrons an atom loses or gains in a chemical reaction |
