Warm-up

1. Warm-up • Draw the Lewis Structure for the following covalent bonds. • CH4 • NH3 • H2O

2. Objectives • SWBAT understandmolecular structure, be able to predictmolecular geometry from the number of electron pairs and to apply the VSEPR model to molecules with double bonds in a virtual laboratory.

3. Polar Covalent Bonds – 2a.3 • When atoms of different electronegativities bond, they don’t share electrons equally. • This unequal sharing of electrons results in a polar covalent bond. How are polar covalent bonds different from regular (nonpolar) covalent bonds?

4. Nonpolar Covalent Bond

5. Slightly Polar Covalent Bond

6. Polar Covalent Bond

7. A. Molecular Structure • Three dimensional arrangement of the atoms in a molecule • Water - bent LQHS

8. A. Molecular Structure • Linear structure – atoms in a line • Carbon dioxide

9. A. Molecular Structure • Trigonal planar – atoms in a triangle • BF3

10. A. Molecular Structure • Tetrahedral structure • methane

11. B. The VSEPR Model • Valence shell electron pair repulsion (VSEPR) model • Molecular structure is determined by minimizing repulsions between electron pairs

12. B. The VSEPR Model • 180o - linear • Two Pairs of Electrons • BeCl2

13. B. The VSEPR Model • 120o – trigonal planar • Three Pairs of Electrons • BF3

14. B. The VSEPR Model • 120o – tetrahedral • Four Pairs of Electrons • CH4

15. The VSEPR Model

16. The VSEPR Model

17. C. Molecules with Double Bonds • When using VSEPR model to predict molecular geometry of a molecule • a double bond is counted the same as a single electron pair

18. Practice – Draw the Lewis Dot and Determine the Shape • CL2 Virtual Lab LQHS

19. Practice – Draw the Lewis Dot and Determine the Shape • SiCl4

20. Practice – Draw the Lewis Dot and Determine the Shape • H2S

21. Practice – Draw the Lewis Dot and Determine the Shape • AsH3

22. Practice – Draw the Lewis Dot and Determine the Shape • BF3