WebMO building, Hybridization, Domain Geometry Names, Polarity, Bond Types

This week we expanded our knowledge about electron and molecular domain geometries by applying the different shapes to models that we built on the computer. We learned how to tell what shape the molecular domain geometry would be by looking at the electron domain geometry. Some of the more confusing geometries were the ones that follow:

This shape is called bent (trigonal planar). It is created from a trigonal planar shape that has 1 lone pair of electrons.

This shape is called trigonal pyramidal. It is created from a tetrahedral shape that has 1 lone pair of electrons.

This shape is called bent (tetrahedral). It is created from a tetrahedral shape that has 2 lone pairs of electrons.

 This shape is called seesaw. It is created from a trigonal bipyramidal shape that has 1 lone pair of electrons.

 This shape is called T-shaped. It is created from a trigonal bipyramidal shape that has 2 lone pairs of electrons.

 This shape is called linear. It is created from a trigonal bipyramidal shape that has 3 lone pairs of electrons.

This shape is called square pyramidal. It is created from an octahedral shape that has 1 lone pair of electrons.

This shape is called square planar. It is created from an octahedreal shape that has 2 lone pairs of electrons.


We used a program called WebMO to build the structures of 13 molecules given to us. We built their molecular structure and then looked at their electrostatic potential maps to see the partial charge if any on the different parts of the molecule. The ball and stick models and electrostatic potential maps can be seen below.

We also talked about hybridization this week. We learned that if a molecule has linear electron domain geometry it will have sp hybridization. We learned that if a molecule has trigonal planar electron domain geometry it will have sp2 hybridization. We also learned that if a molecule has tetrahedral electron domain geometry it will have sp3 hybridization. After tetrahedral, hybridization is not used.


Polarity can be useful in determining what type of bond two elements have with each other. It can be determined by looking a a periodic table that has the electronegativities on it and finding the difference of electronegativity between the two atoms. It is important to know that:

• A difference of 0.0-0.4 indicates the presence of Nonpolar Covalent Bonds 

• A difference of 0.4-1.0 indicates the presence of Moderately Covalent Bonds 

 

• A difference of 1.0-2.0 indicates the presence of Very Polar Covalent Bonds 

 

• A difference of >2.0 indicates the presence of Ionic Bonds

This week we also talked about Sigma and Pi bonds. A sigma bond is a bond that has a bond order of one. A sigma bond can only be a single bond. To make a double bond 1 sigma + 1 pi bond are used. To make a triple bond 1 sigma + 2 pi bonds are used. Sigma bonds form where there is head to head overlap of orbitals. Pi bonds form where there is side to side over lap of orbitals.

Sigma Bond

 Pi Bond

Overall I feel like the WebMO and VSEPR lab report helped me to put all of the ideas of this unit together  and understand how they all are connected. This week I would give my understanding of the material a 8/10. This is because I still have some questions about certain situations but for the most part I understand the material. What helped me to understand the shapes was using my Princeton Review AP Chem Test Book. It has nice diagrams and I was able to bookmark and highlight things in it. I also think that the long discussion that we had on Friday about polarity, bonding and hybridization was also very helpful.