1. WARM UP: 1. Draw the Lewis diagram for the formation of Calcium Sulfide. 2. What happens to e- during ionic bond formation?

2. 1. Two NONMETAL atoms attempt to gain each other’s valence electrons. They do not have enough difference in electronegativity to do so, therefore they share them. 2. The electrons shared are the unpaired valence electrons. 3. The bonded atoms actually become part of each other. This makes for a bond much stronger than an ionic bond. 4. This bond can not be broken by dissolving in water or melting, so covalent compounds never conduct electricity, regardless of the phase (exception later this year). 5. Since no ions are formed, molecular substances will never conduct electricity 6. NO VALENCE ELECTRONS ARE TRANSFERRED, THEY ARE SHARED.

3.  Boron compounds- Many boron compounds do not follow the octet rule.  Hydrogen- cannot possibly fit eight electrons into its outer shell. Why?  Lets do some Lewis Structures of Covalent Compounds.

4. 1. Count the TOTAL number of valence electrons in the molecule. 2. If carbon is present, put it in the middle. If carbon IS NOT present, use the element that is present in the LEAST amount. 3. Start fulfilling Octet to atoms. 4. Fill in the other elements around the central atom. 5. Keep a tally of e- as you go.

6.  CH 4  NH 3  BH 3

7.  Single Bonds- 1 pair of electrons shared.  Double Bond- 2 pair of electrons shared.  Triple bond- 3 pair of electrons shared.  Electrons that are NOT bonded are called “Lone Pairs”

8.  Covalent bonds DO NOT conduct electricity in aqueous solution.  Are covalent compounds Electrolytes?

9.  What is a covalent bond?  What is the difference between an ionic and a covalent bond in terms of electrons?  Write the lewis structure for N 2 O  Tomorrow