So let's suppose we have a certain alky, let's say hexine, for example, and let's write out all different types of isomers of hexine. Now, if we compare the stability of one isomer of hexine to another isomer of exe, we'll see a difference in stability. In other words, some isomers are more stable than other isomers. So in general, why is that? Why is it that some isomers of alkans are more stable than other isomers of that same alkane? So we're going to address that question in this lecture.