Pentadiene, C₅H₈, has three isomers, depending on the position of the two double bonds. Determine the shape of these isomers by using VSEPR theory. Describe the bonding in these molecules by using the valence bond method. Do the shapes agree in the two theories? Use molecular orbital theory to decide which of these molecules has a delocalized π system. Sketch the molecular orbital and an energy-level diagram.