In the previous chapter, we saw that the energies of electron orbits are quantized. It was also men-tioned that dealing with an electron in an atom would require considering the wave character of the moving particle. The question remains as to how we proceed when formulating and solving such a problem. The procedures and methods employed constitute the branch of science known as quantum
mechanics or wave mechanics. In this chapter, we will present only a very brief sketch of this impor-tant topic because it is assumed that readers of this book will have studied quantum mechanics in a physical chemistry course. The coverage here is meant to provide an introduction to the terminology and basic ideas of quantum mechanics or, preferably, provide a review.