Understanding organic reaction mechanisms can be a challenging task for many undergraduate students, particularly those who are nonchemistry majors, despite the fact that organic chemistry is a mandatory course for numerous science and engineering undergraduate programs. The selectivity of a reaction is largely determined by the distribution and…

Students' understanding of the orbital concept has been subject to considerable research and debate and often found at variance with a quantum mechanical ideal. Could it be the case that orbitals as actually used by practising chemists in teaching and research also differ from that ideal? Our experience shows that this might often be the case.…

Describes a conceptual typology of models to help teachers select models appropriate to the cognitive ability of their students. Presents an example of how the systematic presentation of analogical models enhanced an 11th-grade chemistry student's understanding of atoms and molecules. Makes recommendations for teachers. Contains 28 references.…