The nature of the students is that there are some that are interested in this topic in its own right. But many of them want to end up doing organic chemistry and pharmacology, or medicine of some sort. This is a theory which is too much physics for some of them, so you’ve always got to relate it back to their own interests.
Students’ patience in thinking about this material is quite short sometimes. So don’t lecture the material for very long. Have a break and get them to do a problem. Do this after introducing the topic, once it’s getting a little bit more concrete, that is, when they can actually work through a problem.
Lecture for five or ten minutes and use work sheets, which they pick up as they come in. Let them work on the worksheets, then have a discussion and use a response devise, like their mobile phones, to feed back answers.
Introduce quantum mechanics in a very qualitative way, so they don’t get worried about it in a big way or worry about the mathematical treatments. Introduce just the big thing that it can tell us, but not be too concerned about the details. The ideas that flow from the qualitative concept are very important, but the mathematical treatment is not so important to them at that stage.