| A | B |
|---|
| pure substance | substance made of one kind of material |
| element | simplest type of pure substance |
| atom | smallest part of an element (building block of matter) |
| chemical symbol | shorthand for writing an element |
| compound | two or more elements chemically combined |
| molecule | combination of atoms formed from a covalent bond |
| chemical formula | combination of symbols used to represent a compound |
| subscript | indicates the number of atoms in an element |
| chemical equation | symbols, formulas, and numbers used to show a reaction |
| coefficient | indicates the number of molecules of a substance |
