Friday, November 13, 2009

Lecture #21, Friday, November 13th

Today we continued our talk about bonding in molecules by finishing up with non-polar and polar covalent bonds. The larger the difference in electronegativity, the more ionic a bond is and this can enable us to list certain molecules in order of covalent/ionic character.

We then started to talk about Lewis structures and VSEPR shapes. Check out the following link depicting the various VSEPR shapes, which are determined by how many pairs of electrons surround the central atom. We will determine the number of lone pairs and bonding pairs around the central atom based on #1. The number of valence electrons around the central atom and #2. The number of electrons each ligand (or surrounding atom) contributes to each bond.

I will discuss these shapes in great detail on Monday in class and go through various examples. If you are a visual person check out the following website put together by the general chemistry department here at Ohio State. It has an excellent tutorial of what happens to the shapes of molecules as we vary the number of pairs of electrons about the central atom.

I hope everyone has a great weekend :)

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