Below
are links to Physics 2000 at the University of Colorado, Boulder that has a
lot of interactivity and will help you understand Chapter 7. You might need
to install Quicktime. These pages are particularly
useful to get a conceptual grasp of electronic structure and "conversations"
between a professor and several students to get points across. I highly recommend
you take a look at some of these pages; they are really fun and well thought
out. Enjoy!