This site from the Purdue University provides quantum numbers explained in detail and shown how they specify the atomic orbital of each electron and their energy levels. Electronic configurations are explained. Learning exercises with...

Using diagrams, illustrated examples, and student practice this chemistry class tutorial explains quantum numbers.

This site from the Purdue University provides an overview of atomic orbitals and how quantum numbers specify these orbitals. Includes a model that can be rotated and examined in 3D. Includes learning exercises and answers.

Using a Java applet, sets of atomic orbitals are compared with different quantum numbers in order to compare the orbital sizes.