4-Question Guide to Naming Chemistry Formulas - dummies

4-Question Guide to Naming Chemistry Formulas

By John T. Moore, Chris Hren, Peter J. Mikulecky

Part of U Can: Chemistry I For Dummies Cheat Sheet

Need to name a chemical formula and not sure where to start? Here’s a simple list that will point you in the right direction. Answer these questions as you go, and you’ll have your chemical named in no time.

  1. Does the formula begin with an H?

    If so, you more than likely are dealing with an acid. You must apply the rules of acid naming when dealing with these formulas. Remember, if oxygen is present, the substance is considered an oxy-acid and must be named accordingly: Find the name of the polyatomic ion that the oxy-acid contains. If the name ends in –ate, change the ending to –ic. If the name ends in –ite change the ending to –ous. Then simply write acid at the end.

    If the formula contains one positive cation and one negative anion with no oxygen present, then it’s a binary acid and must be named accordingly: Write hydro, write the name of the anion present, and change the ending of the name to –ic. Then write acid after it.

  2. Does the formula contain a metal (not hydrogen)?

    If there’s no metal, you’re naming a covalent compound, so you need to use the covalent prefixes. Be sure to change the ending of the second element to -ide. If there is a metal, then you’re dealing with an ionic compound, so proceed to Question 3.

  3. Is the cation a transition metal (Group B) or a metal with a variable charge?

    If the cation is a Group B metal (or other metal of variable charge, like tin), you need to use Roman numerals to specify its charge. If the cation isn’t a transition metal and you know the charge, you don’t need to specify the charge with roman numerals.

  4. Is the anion a polyatomic ion?

    If so, you have to recognize it as such and have its name memorized (or easily accessible in a nifty table). If the anion isn’t a polyatomic ion, you use an -ide ending.