| A | B |
|---|
| chemical symbol | a shorthand way of representing an element |
| chemical formula | the combination of chemical symbols that represent elements in a compound in the simplest ratios in which these atoms are combined |
| atom | the smallest part of any element that retains all the properties of that element |
| atomic number | the number of protons in the nucleus of an atom |
| electron cloud | the region of an atom in which the electrons orbit the nucleus |
| atomic mass | the number of protons and neutrons in the nucleus of an atom |
| electron | the negatively charged particle around the nucleus of an atom |
| element | a pure substance that contains only one kind of atom |
| matter | anything that has mass and takes up space |
| atomic mass | the average of the masses of all an element's isotopes that are found in nature |
| nucleus | the central part of an atom |
| melting point | temperature at which a substance changes from the solid phase to the liquid phase |
| electron cloud model | the model of an atom that consists of a positive center with electrons circling it |
| liquid | matter with no definite shape but with a definite volume |
| homogeneous mixture | a mixture that appears the same throughout |
| physical property | a property of matter that can be observed or measured without changing the composition of the matter |
| gas | state of matter in which the matter has no definite shape or volume |
| evaporation | vaporization that takes place on the surface of a liquid |
| solid | state of matter in which the matter has both a definite volume and a definite shape |
| chemical change | process by which a substance becomes a new and different substance |
| density | measurement of how much mass is contained in a given volume of an object: mass per unit volume |
| mass | amount of matter in an object |
| heterogeneous mixture | a mixture that does not appear the same throughout |
| mixture | matter that consists of two or more substances mixed but not chemically combined |
| plasma | state or phase of matter consisting of low density, super-heated gas in which electrons and nuclei are free to move at random |
