Skill Sheet 19-C
Naming Chemical Compounds
Compounds have unique names that identify them for us when we study chemical properties
and changes. Predicting the name of a compound is fairly easy provided certain rules are kept
in mind. In this skill sheet, you will practice naming a variety of chemical compounds.
1. Chemical formulas and compound names
Chemical formulas tell a great deal of information about a compound—the types of elements
forming the compound, the numbers of atoms of each element in one molecule, and even some
indication, perhaps, of the arrangement of the atoms when they form the molecule.
In addition to having a unique chemical formula, each compound has a unique name. These
names provide scientists with valuable information. Just like chemical formulas, chemical names
tell which elements form the compound. However, the names may also identify a “family” or group
to which the compound belongs. It is useful for scientists, therefore, to recognize and understand
both a compound’s formula and its name.
2. Naming compounds
Naming ionic compounds is relatively simple, especially if the compound is formed only from
monoatomic ions. Follow these steps:
1. Write the name of the first element or the positive ion of the compound.
2. Write the root of the second element or negative ion of the compound.
For example, write fluor- to represent fluorine, chlor- to represent chlorine.
3. Replace the ending of the negative ion's name with the suffix -ide.
Fluorine → Fluoride; Chlorine → Chloride
A compound containing potassium (K
) and iodine (I
) would be named potassium iodide.
) combined with sulfur (S
) would be named lithium sulfide.
Naming compounds that contain polyatomic ions is even easier. Just follow these two steps:
1. Write the name of the positive ion first. Use the periodic table or an ion chart to find the
2. Write the name of the negative ion second. Again, use the periodic table or an ion chart to find
) would be called aluminum sulfate.
A compound containing aluminum (Al
) and sulfate (SO
A compound containing magnesium (Mg
) and carbonate (CO
) would be called