Naming Ionic Compounds
The chemicals that you will encounter during your chemistry course(s) will undoubtedly fall into many different categories: ionic, binary molecular, acid, coordination compounds, and organic compounds. Each of these classes of compounds uses a unique naming system. In Chem I and II, you will be responsible for naming and writing formulas for commmon ionic compounds, binary molecular compounds, acids, and simple organic compounds.
Since each of these classes of compounds uses a unique naming system, the first step in correctly naming a compound is to identify the type of compound that it is. You can do this by looking at the formula for the compound.
Ionic Compounds: As a rule of thumb, ionic compounds generally consist of a metal and one or more non-metals. The main exception to this are those ionic compounds that contain the ammonium ion (NH4+). All compounds whose formulas begin with NH4+ are also ionic.
Binary Molecular Compounds: As a general rule, binary molecular compounds contain two different non-metals.
Acids: The formulas for inorganic acids (those that do not contain a C-C skeleton) will start with "H" (or H2 or H3, etc).
To name an ionic compound you simply need to find the names of the cation and anion present in the compound.
Identify the cation:
The cation is always written first in the formula for an ionic compound.
Most cations are monoatomic (consist of only 1 atom that has lost electrons to become positively charged) metal ions. In these compounds, the cation will be the first element written.
Many (but not all) transition metals plus tin, bismuth, and lead can form more than one cation. Use Roman numerals in parentheses after the name of the element to indicate the charge of such ions.
The only common polyatomic ion that you will encounter is the ammonium ion (NH4+).
Identify the anion:
Cover up the cation. Everything that is leftover will be the anion.
Write the name of the ionic compound by writing the name of the cation followed by the name of the anion.
Example: Write the correct name for the compound whose empirical formula is Na2SO4.
Example: Write the correct name for the compound whose empirical formula is (NH4)2CO3.
Example: Write the correct name for the compound whose empirical formula is SnO2.
Name the following compounds: