So let's review. The Sigma bond contains more S character and is therefore lower in energy and more stable or stronger. Because remember, the more stable something is, the more stronger it is then the Pi bond. Therefore, the Pi bond is less stable because it's higher in energy, and therefore it's more reactive. Now, whenever we input energy to break our Pi bond or to break our double bond, our pi bonds break first. So let's look at one more important detail about our double bonds.