1. IIIIII Molecular Geometry Molecular Structure

2. A. VSEPR Theory  Valence Shell Electron Pair Repulsion Theory  Electron pairs orient themselves so that valence electrons are as far apart as possible

3. A. VSEPR Theory  Types of e - Pairs  Bonding pairs - form bonds  Lone pairs - nonbonding e - Lone pairs repel more strongly than bonding pairs!!!

4. A. VSEPR Theory  Lone pairs reduce the bond angle between atoms. Bond Angle

5.  Draw the Lewis Diagram.  Count up e - pairs on central atom.  double/triple bonds = ONE pair (for shape purposes only!!)  Shape is determined by the # of bonding pairs and lone pairs. Know the 8 common shapes & their bond angles! B. Determining Molecular Shape

6. C. Common Molecular Shapes 2 total electron pairs *2 bonding pairs *0 lone pairs LINEAR 180° BeH 2 Note: Beryllium does not follow the octet rule. Beryllium is complete with 4 valence electrons

7. 3 total electron pairs *3 bonding pairs *0 lone pairs TRIGONAL PLANAR 120° BF 3 C. Common Molecular Shapes Note: Boron is also an exception to the octet rule. Boron is complete with 6 valence electrons

8. C. Common Molecular Shapes 3 total pairs *2 bonding pairs *1 lone pair BENT <120° SO 2

9. 4 total pairs *4 bonding pairs *0 lone pairs TETRAHEDRAL 109.5° CH 4 C. Common Molecular Shapes

10. 4 total pairs *3 bonding pairs *1 lone pair TRIGONAL PYRAMIDAL 107° NH 3 C. Common Molecular Shapes

11. 4 total pairs *2 bonding pairs *2 lone pairs BENT 104.5° H2OH2O C. Common Molecular Shapes

12. 5 total pairs *5 bonding pairs *0 lone TRIGONAL BIPYRAMIDAL 120°/90° PCl 5 C. Common Molecular Shapes

13. 6 total pairs *6 bonding pairs *0 lone pairs OCTAHEDRAL 90° SF 6 C. Common Molecular Shapes

14. PF 3 4 total 3 bond 1 lone TRIGONAL PYRAMIDAL 107° F P F F D. Examples

15. CO 2 O C O 2 total 2 bonding pairs 0 lone LINEAR 180° D. Examples

16. IIIIII Molecular Polarity Molecular Structure

17. Molecular Polarity Polar Molecule: Molecule that has a partially positive end and a partially negative end. (It has electrical poles) There is an uneven distribution of electrons in the molecule

18. A. Dipole Moment  Direction of the polar bond in a molecule.  Arrow points toward the more electronegative atom. H Cl ++ --

19. B. Determining Molecular Polarity  Depends on:  dipole moments  molecular shape

20. B. Determining Molecular Polarity  Nonpolar Molecules  Dipole moments are symmetrical and cancel out. BF 3 F F F B

21. B. Determining Molecular Polarity  Polar Molecules  Dipole moments are asymmetrical and don’t cancel. net dipole moment H2OH2O H H O....

22. B. Determining Molecular Polarity  Polar molecules have...  asymmetrical shape (lone pairs) or  asymmetrical atoms (attached atoms are different)

23. B. Determining Molecular Polarity  Nonpolar Molecules have…  No lone pairs  All attached atoms are the same