Basic binary (meaning made of "two halves") chemical nomenclature can be roughly divided into two categories:

IONIC These compounds are made of sets of IONS and the representative particle is a FORMULA UNIT.

COVALENT These compounds are made of non-metals and the representative particle is a MOLECULE.

In this section, we will address the nomenclature rules for each category separately (since the rules are quite different.)

1. Determine the symbols for each non-metal from the name in the compound.

Carbon dioxide

"carbon" is represented by the symbol "C"

"oxide" is represented by the symbol "O"

2. Using the meaning of the prefixes, identify the number of each non-metal needed:

1 mono-- (note: the first non-metal does not use the prefix "mono.")
2 di--
3 tri--
4 tetra --
5 penta --
6 hexa--
7 hepta --
8 octa --
9 nona --
10 deca --

Carbon dioxide -- the carbon is singular and the oxygen has 2 atoms

3. Write the formula using the correct symbols and subscripts.

CO₂

1. From the formula, identify the correct name for each non-metal.

2. Using the prefixes used in the name, write them as subscripts. The number "1" is not written as a subscript but all others are.

1. Determine what group the metal or non-metal is in.

2. Write down the charges for each ion -- the symbol for the element plus the charge written as a superscript.

3. Determine how many of each ion you need in order to have an overall 0 charge. Use subscripts to identify that quantity. We do NOT write the subscript "1" (it is implied).

1. Determine the correct name of the metal and the non-metal using the symbols in the formula.

2. The metal is always written first -- just write down the name of the element.

3. The non-metal is written second -- substitute the suffix --ide for the ending of the non-metal.

1. You will use the general procedure as described above.

2. Identify the metal with its charge.

3. Identify the polyatomic ion (as indicated on your polyatomic ion reference sheet).

4. Determine how many of each ion you need to have an overall charge of 0.

5. Use subscripts to identify that quantity.

1. From the formula, identify the metal with its polyatomic ion name (as indicated on your polyatomic ion reference sheet).

2. Write down the name of the metal first.

3. Write down the name of the polyatomic ion second.

1. Use the general process as you did for other ionic nomenclature.

2. The non-group I, II (or Al or B) metals -- usually the transitional metals -- can have more than one charge. The roman numeral indicated in the name indicates which positive charge you have for that particular metal ion.

3. Write the formula using the correct charge as indicated.

1. For the non-group I, II (or Al or B) metals -- usually the transitional metals -- identify what the name of the element is. You will need to figure out what charge that metal ion has by first checking the rest of the compound.

2. Identify the symbol of the non-metal and its charge.

3. Going "backwards" using the subscripts given, determine the charge of the transitional metal.

4. Use a roman numeral (in parentheses) to indicate the correct charge for the transitional metal.

PRACTICE PROBLEMS

Write the correct formula. Remember, if the compound is ionic, you MUST include charges in the written formula.

Ammonium carbonate
Iron (III) hydroxide
Copper (I) nitrate
Carbon tetrabromide
Aluminum phosphate
Barium acetate
Mercury(I) chromate
Lead (II) nitrite
Sodium sulfite
Cobalt (II) phosphate
Silicon tetrachloride
Magnesium oxide
Potassium dichromate
Nickel(II) chlorate
Barium iodide
Chromium (III) oxide
Carbon monoxide

Write the correct compound name.

K₂O
Al₂S₃
SF₆
Hg(HCO₃)₂
Mg₃(PO₄)₂
Fe(NO₃)₃
Zn(C₂H₃O₂)₂
K₂CO₃
P₂Cl₅
KCl
BeF₂
AlPO₄
NO₃
Sr₃N₂

Click here for solutions

Click here to go to a nomenclature site at Widener University (Chester, PA).