A Simple VSEPR Demonstration To assist my students in visualizing the Valence Shell Electron-Pair Repulsion (VSEPR)geometries, I use a 2-in. ring and six snap hooks from the hardware store. I attached a l-m length of latex tubing to each snap hwk. The ring represents the central atom while the student's hand holding the end of the latex tubing represents a pair of electrons. I attach 2 6 snap hwks to the ring and have students hold the ends of the latex tubing. The students are instructed to get as far away from one another as they can without stretching the latex tubing. It may be convenient to have a large cardboard mmpass so that the approximate angle can be read. When four snaps are attached, the students normally take a square planar eonfiguration. After the angle is read, they are asked to deviate from the plane. A very tall student or a step stwl is helpful a t this point. They also need help when it mmes to the trigonal bipyramidal geometry. This demonstration seems to work well in a large lecture setting. It is fast and the model is large enough to be easily seen. Finally, the students seem to genuinely enjoy participating in the demonstration. Frederick A. Kundell Salisbury State University Salisbury, MD 21801
Volume 69 Number 4 April 1992
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