1. VSEPR
A little bit of Chapter 9

2. VSEPR Theory V alence S hell E lectron P air R epulsion
repulsion between pairs of electrons around an atom cause them to be as far apart as possible
used to predict the geometry of molecules

3. Molecular Shapes diatomic molecules will always be linear
all other molecules can have different shapes based on the number of charge clouds around the central atom
charge clouds include:
bonding pairs
lone pairs

4. What do you need to know?
the geometrical shapes compounds will form based on bonds & lone pairs
The bond angles for the main geometries (those with no lone pairs)
the next slide sums it all up…

6. Polarity For a compound to be polar, 2 qualifications must be met:
the bonds must be polar AND
the overall geometry must be asymmetrical
Think vectors from physics 

7. How can bonds even happen?
bonding electrons are usually on different energy levels and different sub-levels
to even things out, atoms form hybrid orbitals (like the mutts of the orbital world)
For more info about hybrid orbitals, we are going to watch a little video…
Hybridization Video

8. Sigma and Pi bonds all single bonds are sigma
all double bonds are combo sigma and pi bonds
all triple bonds are combo one sigma and 2 pi bonds

9. Practice Consider the chemical species IF5 & IF4+
Draw the Lewis structure and make a rough 3D sketch of each species.
Identify the orbital hybridization and the VSEPR geometry of each.
Identify the approximate bond angles of each species.
Predict which, if any, is a polar species. Justify your answer.
Predict the most probable oxidation number of the iodine atom in each species.
Would you expect the conversion of IF5 to IF4+ to be endo- or exothermic. Explain.