Aim: What properties do Ionic Compounds have? Do Now: 1.What type of ions are in involved in ionic compounds? 2.What type of elements are usually involved in forming ionic bonds? 3.Explain, in terms of electrons, how ionic bonds are formed.

Questions to Answer During Demo 1.What is electricity? 2.What happened to the light bulb when the two electrodes were touching? 3.What happened to the light bulb when the electrodes were placed in water? 4.What happened to the light bulb when the electrodes were placed in salt water?

Ionic Bonding Process

Properties of Ionic Compounds Ionic substances form giant ionic crystals containing oppositely charged ions. High melting and boiling points - Ionic bonds are very strong - a lot of energy is needed to break them. So ionic compounds have high melting and boiling points Conductive when liquid - Ions are charged particles, but ionic compounds can only conduct electricity if their ions are free to move. Ionic compounds do not conduct electricity when they are solid - only when dissolved in water or melted.

Example: Aluminum Chloride Step 1: Step 2: Step 3: 13 Step 4: AlCl 3 Criss-Cross Rule Al Cl write out name with space write symbols & charge of elements criss-cross charges as subsrcipts combine as formula unit (“1” is never shown) Predicting Chemical Formula of Ionic Compounds

Example: Aluminum Chloride Step 1: AluminumChloride Step 2: Al 3+ Cl 1- Step 3: Al Cl 13 Step 4: AlCl 3 Criss-Cross Rule

Example: Aluminum Oxide Step 1: Aluminum Oxide Step 2: Al 3+ O 2- Step 3: Al O 23 Step 4: Al 2 O 3 Criss-Cross Rule

Example: Magnesium Oxide Step 1: Magnesium Oxide Step 2: Mg 2+ O 2- Step 3: Mg O 22 Step 4: Mg 2 O 2 Step 5: MgO Criss-Cross Rule

Practice Using Criss-Cross Method to Predict Ionic Formulas Predict the formulas of the ionic compounds formed form the following elements. a.Potassium and oxygen b.Magnesium and nitrogen K +1 O -2 K2OK2O Mg +2 N -3 Mg 3 N 2