Question

Molecular Models and Intramolecular Spatial Relationships/VSEPR Theory

Write a descriptive outline of the steps in the process you would use to determine the shape of a molecule starting from the molecular formula. PLEASE be descriptive!!!

The outline needs the details of the process to determine the Lewis structure. A single line stating "Draw Lewis structure" is not sufficient. This is an appropriate heading, but there should be sub-headings describing the process of drawing a Lewis structure.

Answer 1

The shapes of molecules can be determined as per VSEPR theory,

1. Draw the Lewis structure for the molecule of interest and count the number of electron groups surrounding the central atom. Each of the following constitutes an electron group:
   • a single, double or triple bond (multiple bonds count as one electron group)
   • a lone pair
   • an unpaired electron
2. Predict the arrangement of electron groups around each atom by assuming that the groups are oriented in space as far away from one another as possible.
3. The shapes of larger molecules having more than one central are a composite of the shapes of the atoms within the molecule, each of which can be predicted using the VSEPR model.