Formula Writing AND Naming - Covalent Compounds

If you know your geometry prefixes, you're in luck.

Any two non-metals can combine in a number of ways unlike ionic compounds that have fixed ratios based on the charges. As a result, covalent compounds are identified WITH PREFIXES that indicate the amount of each specific element.



The only one main rule to remember is that the prefix "mono-" is not used with the first element, just the second one. A compound starting with "Carbon..." or "Phosphorus..." only has one carbon, or one phosphorus, respectively.

For formula writing:

Dinitrogen Tetroxide

The prefixes tell me I have 2 nitrogens and 4 oxygens so: N2O4 

Dihydrogen Monoxide

The prefixes tell me I have 2 hydrogens and 1 oxygen: H2O

For naming, when given a formula, I look at the subscripts in order to determine the prefixes:

Cl2O7

I have 2 chlorines and 7 oxygens, so: Dichloride Heptoxide

SCl6

I have 1 sulfur and 6 chlorines, so: Sulfur Hexachloride

There is not as much of a process compared to ionic compounds. The key thing is to not get covalent compounds mixed up with ionic compounds.

Here's extra practice: Compound Naming and Formula Writing

This practice also includes ionic compound naming which I had not covered, but it doesn't hurt to try.