Ch. 4 (Naming Compounds Tutorial)

Naming Compounds: Introduction

Goals

After working through the exercises on this webpage you will be able to:

Determine if a compound is ionic or molecular.
Name Ionic compounds and decide whether they require a Roman numeral or not.
Name Molecular Compounds using prefixes.

Review Example One: NaCl

Before we begin learning how to name compounds, let's take just a minute to review how to write the formula of a compound. Remember, that you want to balance the charges (or oxidation numbers) so that overall the compound has no charge, or zero oxidation state. Using Lego's as a model, NaCl would look like this:

Notice that the "1+" charge on Na and the "1-" charge on Cl cancel each other out.

Review Example Two: CaCl₂

The calcium ion and the chloride ion combine differently in CaCl₂. Here is a picture:

Notice that it took two Cl^- ions to cancel out the Ca²⁺. Think of Ca²⁺ as being a longer Lego. It takes two Cl^- ions to cancel the entire charge.

Ionic or Molecular?

To tell if a compound is ionic or molecular, you simply look at the first element:

If the first element is a metal, the compound is IONIC
If the first element is a non-metal the compound is MOLECULAR

Yes, it is that simple.

But What About the Metalloids?

For naming purposes, treat any element to the left of the metalloid line (the staircase) as a metal. Any to the right are treated as non-metals.

Examples

ZnCl2

Ionic (zinc is a metal)

CO2

Molecular (carbon is a non-metal)

GeF4

Ionic (germanium is on the metal side)

Report abuse