Hi. I am wondering when should we use hybridized orbital? For PH3, we don't use hybridized orbital because it could be described by the valence shell method. The valence shell orbital diagram: p: [Ne] 3s:up down 3p: up up up And we have 3 up. so the 3 extra electrons from hydrogen could fit into there. Therefore we don't need hybridized orbital. But when do we need it?