Looking for resources on teaching VSEPR theory.  I know there is a commonly done lab with balloons out there.  I've searched google, but don't really like anything thats come up.  Any one have a good lab for that? Thanks!

Chris Leverington
Chris Leverington
3940 Activity Points

Hi Chris, 

I am in the same boat as you.  I have not found many resources (good or bad) for high school students regarding VSEPR.  One article I am using with good success is from the Journal of College Science Teaching. (As a matter of fact, I am teaching it tomorrow.)  The article explains using Magnetix or some other type of child's building toy to create these models using a ball bearing as the central atom, magnets as the electron domains, and paper clips to represent the lone pairs.  My students find the three dimensional models helpful in identifying the the electron domains and since they aren't static models, they can be manipulated easily.  My children are grown and don't use the Magnetix anymore so they have become a permanent fixture in my classroom.

To facilitate the demonstration, I divide students into groups of two and give each pair of students a tray with multiple ball bearings, small paper clips, and the magnets from the Magnetix kits.  At first, I demonstrate a linear arrangement with two steric numbers and no lone pairs.  Then I we add electron domains, but no lone pairs and we explore how the molecular geometries arrange three dimensionally.  We then progress through the molecular geometries to include lone pairs.  Students predict how they think the molecule will look and then we construct the model as a class.  Students make adjustments to their models as necessary. 

Before we do this activity, students have completed two POGILs.  The first POGIL shows the connections between Lewis dot arrangement and VSEPR molecular geometries   In the second POGIL , students continue to explore the relationship between Lewis dot arrangements and the molecular geometries. They end this POGIL by using ball and stick kits to show the various models mentioned in throughout the POGIL.  

Another place you might look is at PhET.  They have an HTML5 computer simulation called Molecule Shapes that is another way that students can build models.  PhET offers several teacher resource options and student guides that are free (you just need to sign up for an account).  My students have also found this simulation to be helpful in conjuction with the hands-on activity.  The years in which we just did the computer simulation many students were still a little confused. I would say that whatever you find to use make sure you include physical modeling along with the 2-D shorthand because it helps students develop their spatial understanding. 

I would be interested in knowing more about the balloon lab.  That sounds very interesting. Care to post it here?

What are others doing at the high school level to teach VSEPR in their chemistry classes?

 

 

Ruth Hutson
Ruth Hutson
62700 Activity Points

As Ruth mentioned, I've used the PhET simulation on molecular shape. It is easy to use and very informative for students. 

Emily Faulconer
Emily Faulconer
3030 Activity Points

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