Determining the molecular shape

[806021969]

When determining the molecular shape of a molecule, do we have to look at the location of electrons and if so how can we approach looking at the structure to see what molecular shape it is?

[Valeria Perez 3J]

When you determining the molecular shape and you first draw your Lewis structure, the lone pair placement will not be entirely accurate on your Lewis Structure. In order to help you determine your shape, you want to take your lone pairs and place them as far away from each other as possible. This usually lands them on the equatorial plane, 180 degrees from one another, if there are multiple. If there is only one, then your lone pair will have repulsive forces against the outer atoms, and it is important to take that into account, as it can affect what appears to be, for example, a linear molecular shape, and turn it into a bent or angular shape. In summary, in order to figure out your lone pair placement, you want to place them as far apart to account for the electron repulsions. Hope that helps!