Shapes of Molecules

Once we have the Lewis Diagram for a molecule, we can infer its shape.

Regions of Electron Density: We talk about "regions of electron density when explaining shapes. These are:

1. Lone pairs of electrons around the central atom
2. Bonds between the central atom and other atoms.

There are some shapes and bond angles to remember. We used toothpicks to represent regions of electron density, and marshmallows to represent bonded atoms.

For two regions of electron density (eg carbons dioxide), there is only one shape (linear).

There are two factors that affect shape:

1. Regions of electron density (lone pairs and/or bonds) around the central atom
2. Number of atoms bound to the central atom