Naming Ionic and Covalent Compounds

Naming a compound gives us an easier way to discuss it in conversation. Just imagine having to say “aitch-gee-too-bee-ar-too dissolved in aitch-too-oh” and the like multiple times per conversation - it’s much more natural to say “mercury bromide dissolved in water”! Naming a compound properly gives us this ability to talk about a compound naturally without losing any information about the compound.

• Recall that covalent compounds are those that involve more than one atom bonded together by the sharing of electrons. You’ll know for certain that you are dealing with a molecular compound if only nonmetals are present.
• To name a covalent compound, you need the molecular formula, knowledge of the prefixes used for naming, and a way to look up the name of an element given its atomic symbol. With this information in hand, you can follow the naming scheme for covalent compounds:

• First, identify the elements present.
• Second, look at the subscript of each element to determine which prefix to use. (If an element does not have a prefix, assume that the subscript is “1.”
• Third, apply the above naming scheme. (Note: If the prefix of the first element would be “mono-”, it is not needed.)

TIP!: Get used to what part of an element’s name is the “root” early, because it’s not always easy to tell by looking!

• Recall that ionic compounds consist of a positively charged cation and a negatively charged anion.
• Ions (of either variety) may contain either a single element or more than one element. (When an ion consists of more than one element, we refer to it as a “polyatomic ion.”)
• To recognize an ionic compound, look for the presence of a metal or a known polyatomic ion- once you find one, you more than likely have an ionic compound.
• When we name an ionic compound, we do not use prefixes; instead, use one following naming schemes: