What Shapes Do Simple Molecules Make

Learn the basics about the shapes of simple molecules, when learning about properties of matter. In reality the shapes of simple molecules are 3-D molecules and should be visualised as such. Imagine now the central carbon atom surrounded by a sphere. We now need to position the hydrogens in such a way as to ensure that all the paired electrons in the covalent bonds are as far away from each other as possible. This is known as electron pair repulsion theory as the electron pairs and bonding pairs repel one another and we will end up with a triangular pyramid shape at the bottom, with a hydrogen at each corner and a fourth hydrogen coming out of the top. This shape with four bonding pairs is known as a tetrahedral molecule with a bond angle of 109 degrees. In water there are two bonding pair electrons and two lone pair electrons. The lone pair electrons will repel the binding pair electrons even more than before creating a v shaped or bent molecules with a bind angle of 104 degrees. All three of these molecules were based on 4electron pairs, either binding pairs or lone pairs. They were therefore all based on the original tetrahedral molecule however the bond angle changed due to the extra repulsion due to the lone pair electrons.