Hybridization, Sigma/Pi bonding, and WebMo molecules

This week was a very eventful one in Dr. J's classroom. We learned how molecules can be classified using hybridization, what sigma and pi bonding is, and then progressed to complete the VSEPR lab with its new addition of the WebMO molecular models lab. We also reviewed some concepts such as polarity and the dipole moment that weren't very clear before. These concepts were very necessary knowledge we needed to comprehend moving forward towards our test on Tuesday.

Hybridization surprised a lot of people. I had no idea what this was just going off the information from the lectures. As we worked through it in class though, Dr. J came up with a very simple and easy way for me to tell a molecule's hybridization. All we really needed to do was look at our given molecule's central atom. This atom would give us all the information we needed to know. To find the hybridization of a molecule, you need to only look at the number of electron domains in the central atom. If it had two electron domains, the hybridization would be sp.  If it had three electron domains, the hybridization would be sp2. If it had four electron domains, the hybridization would be sp3. You an only classify molecules through hybridization through four electron domains, so if a molecule had 5 domains, you could not classify it through hybridization. Examples of hybridization in molecules different types of molecules be seen below.

Sigma and Pi bonding was also another very confusing subject. The lecture also gave me absolutely no help whatsoever as to comprehending what these bonds are or how they are really formed. However, just as with hybridization, as we went over the concept of Sigma and Pi bonding in class, it became a whole lot more clear what Sigma and Pi bonds really were. Basically, a single bonded molecule would only have Sigma bonds dependent upon how many bonds you have. Take for instance, F2. F2 has one, single bond. This single bond indicates that there is one sigma bond present. A double bond however means that the molecule has one sigma bond and one pi bond. A triple bond on the other hand, indicates that the molecule has one sigma bond and two pi bonds. Take for instance the element C2H2 above. There are two single bonds and one triple bonds. The two single bonds indicate there are two sigma bonds. Add that to the one sigma and two pi bonds present in the triple bond, and you can see that C2H2 has 3 sigma bonds and two pi bonds. The powerpoint below can provide a little more assistance if needed.

Sigma and Pi bonds

The WebMO lab really cleared things up for a lot of people. This lab allowed us to create models of each of the thirteen molecules we had in our lab. Some of these included NSF, H20, and BeF2. From these models, we were able to tell a molecule's polarity, charge, dipoles, shape, and bond angles. The polarity could be seen looking at the molecule's colors when looking at the WebMO diagram. If symmetrical, the colors would indicate overall that the molecule was not polar. If not symmetrical though, the colors would indicate that the molecule is overall polar. We could tell the charge, dipoles, shape, and bond angles by just looking at the diagram and information listed below the model for most molecules.

Overall, I learned a lot about Hybridization, Sigma and Pi bonds, and gained tons of useful knowledge from the WebMO diagrams. My participation overall this week has been pretty good, especially in the WebMO lab. I would rate my understanding of the concepts this week at a 7 out of 10. I got a lot of the information, just not every single bit. I still need to work on the dipole moment of molecules because I am not quite sure how to calculate that still.