1. Ionic Bonds and Ionic Compounds
7.2
Page 194

2. Formation of Ionic Compounds
Compounds composed of cations or anions are called ionic compounds.
Usually composed of metal cations and nonmetal anions.
NaCl
Ionic compounds are electrically neutral.
The total positive charge of cations equals the total negative charge of anions.

3. Ionic Bonds
Anions and cations attract one another by their electrostatic forces. These forces are called Ionic Bonds.
When sodium and chlorine react to form a compound, the sodium atom gives its one valence electron to a chlorine atom.
They form an ionic bond in a one-to-one ratio.

4. Formation of Ionic Compounds

5. Forming Ionic Compounds
Show how Bromine (Br) reacts with Aluminum (Al).

6. Formula Units
Chemist represent the composition of substances by writing chemical formulas.
Chemical formulas show the kinds and numbers of atoms in the smallest representative unit of a substance. They actually refer to ratio known as a formula unit.
The lowest whole-number ratio of ions in an ionic compound.
Write the formula unit for Magnesium chloride.

7. Properties of Ionic Compounds
Most are crystalline solids at room temperature.
Arranged in repeating three-dimensional patterns.
Have high melting points.
Can conduct an electric current when melted or dissolved in water.

8. Coordination Number
The number of ions of opposite charge that surround the ion in a crystal.
See page 198.