Forming Ionic Bonds When atom gains or loses electrons, it becomes a charged ion. The charge on the ion explains how many electrons an atom has gained or lost. The ionic charge is also called the oxidation number. Ionic bonds are formed because of the attraction between a positive ion (cation) and negative ion (anion).

Electron Dot Structures for Ionic Compounds 1. Write the electron dot structure for the metal and nonmetal. 2. Draw an arrow to show how the electron is transferred. 3. On the other side of the arrow, redraw the dots for the ions. There will be no dots on the cation and 8 dots around the anion. 4. Oxidation Numbers (ionic charge) should add up to ZERO!

Example Drawing Oxidation Number (Ionic Charge)

Examples: KF Potassium and Fluorine

Examples: Na2O Sodium and Oxygen

Examples: BeCl2 Beryllium and Chlorine

Examples: Al2S3 Aluminum and Sulfur [ ] [ ] [ ]