1. WARM UP Name the following: – BCl 3 SiO 4 C 6 S 5 Write formulas for the following: – dibromine octaselenide – dihydrogen monoxide

2. Covalent and Molecular Crystals

3. Bond Enthalpy/Energy Measurement of strength of covalent bonds – Found by adding heat to break bonds – Higher enthalpy/energy = stronger

4. Types of Bonds Single – Longest, weakest Double – Shorter, stronger Triple – Shortest, strongest

5. Types of Bonds Polar – + and – ends Non-polar – No charges

6. Crystal Structures Covalent Crystals – Network of covalent bonds Need multiple unpaired e - C = diamonds and graphite – Extremely strong Diamonds in 3D Graphite in 2D (planes)

7. Crystal Structures Molecular Crystals – Molecules stuck, but not bonded No extra e - Sugar – Very weak Low melting and boiling points

8. WRAP UP 1. Compare and contrast molecular and covalent crystals.

9. WARM UP “The miracle is this – the more we share, the more we have.” – Leonard Nimoy 1.Do you agree with this? Why? 2.How can you apply this to your life? 3.How can you apply this to Chemistry?

10. WRAP UP “Destiny is not a matter of chance; it is a matter of choice.” 1.What does this mean to you? 2.How can you apply this to tomorrow’s test?