Hooke's law states that the force required to stretch/compress a spring is proportional to the distance stretched. Meanwhile, electromagnetic interactions between particles obey an inverse-square law with respect to distance. So, if as a spring is stretched, it's composite particles get farther apart from each other, why does the force required to stretch it increase? I know that Hooke's law is only an approximation, but it works quite well. What goes on at the microscopic level which keeps the increased distance between particles from reducing the attractive force between them? If there is a quantum mechanical answer which reveals something special about chemical bonds, I can accept that I am too ignorant of that field to understand the answer as of yet.