| Atomic weight | the average atomic mass for a naturally occurring element, expressed in atomic mass units. |
| Empirical formula | the formula of a substance written with the smallest integer subscripts |
| Molecular formula | a chemical formula that gives the exact number of different atoms of an element in a molecule |
| Molecular weight (MW) | the sum of the atomic weights of all the atoms in a molecule. |
| Percentage composition | the mass percentages of each element in the compound |