| A | B |
|---|
| matter | anything that occupies space and has mass |
| element | pure substance that cannot be broken down by chemical or physical means |
| compound | substance containing two or more elements chemically combined |
| atom | smallest unit of an element that retains the properties of the element |
| proton | particle inside the nucleus of an atom with a positive charge |
| electron | particle outside the nucleus of an atom with a negative charge |
| neutron | particle inside the nucleus of an atom with no charge |
| nucleus | in an atom, the central core that contains protons and neutrons |
| atomic number | number of protons in an atom's nucleus; is unique for each element |
| isotope | form of an element; same number of protons but different number of neutrons |
| ionic bond | bond formed by the attraction of oppositely charged ions |
| ion | atom that is electrically charged as a result of gaining or losing an electron |
| covalent bond | chemical bond formed by the sharing of electrons |
| molecule | two or more atoms held together by covalent bonds |
| chemical reaction | breaking and formation of new chemical bonds that result in new substances |
| reactant | starting material for a chemical reaction |
| product | material created as a result of a chemical reaction |
| polar molecule | molecule in which opposite ends have opposite electric charges |
| hydrogen bond | weak bond between polar molecules |
| cohesion | tendency of molecules of the same kind to stick to one another |
| adhesion | attraction between unlike molecules |
| acid | compound that donates H+ ions to an aqueous solution; pH < 7 |
| base | compound that removes H+ ions from an aqueous solution; pH > 7 |
| pH scale | scale used to describe how acidic or basic a solution is; range is 0 to 14 |
| aqueous solution | solution in which water is the solvent |
