Discusses the problem of symmetry avoidance using water as an historical example. Uses simple pi systems for the analysis. Provides methodology and examples. Investigates two naive arguments. (MVL)

Discusses a new method for determining the eigenvalues of the Schroedinger equation when the potential energy function does not have a simple form. Describes the mathematical methods and provides an application. Lists limitations to the method. (MVL)

Describes several common synthetic organic transformations involving alkenes, alcohols, alkyl halides, and ketones. Includes concepts on kinetic versus thermodynamic control of reaction, rearrangement of a secondary carbocation to a tertiary cation, and the effect of the size of the base on orientation during elimination. (MVL)

Points out a misconception that is reinforced in many elementary and advanced chemistry texts. Discusses the general limitations of the orbital concept. Notes misconceptions related to the transition elements and their first ionization energies. (MVL)

Explores the structural behavior of polyenic pi systems such as isomerization and conjugation. Uses the simultaneous spectrophotometric analysis of a beta-carotene and lycopene mixture. Presents an empirical method to determine the number of double bonds in the polyenic carotenoid. (MVL)

Notes two uses of computer spreadsheets in the chemistry classroom. Discusses the general use of the spreadsheet to easily provide changing parameters of equations and then replotting the results on the screen. Presents a molecular orbital spreadsheet calculation of the LCAO-MO approach. Supplies representative printouts and graphs. (MVL)

Presents an exercise to get students more intimately involved in the three dimensional nature of basic units by constructing models. Uses balsa wood, glue, sandpaper, and a square. Studies seven crystals: cubic, hexagonal, monoclinic, orthorhombic, rhombohedral, tetragonal, and triclinic. Plans are available for a Macintosh computer. (MVL)