Describes a laboratory activity in which polystyrene spheres in two preassembled motifs must be arranged to form a tetrahedral structure. (MLH)

Describes the use of balloon models to illustrate chemical bonding in atoms. (BR)

Examines the phenomenon of water drops that float on water at room temperature. Describes experiments that have been done to study this phenomenon. (MA)

This is part two in a series on classroom demonstrations of polymer principles. Described is how large molecules can be assembled from subunits (the process of polymerization). Examples chosen include both linear and branched or cross-linked molecules. (RH)

Presents an activity in which students gather their own snowflake collection in search of matching crystals. Students stretch plastic wrap over embroidery hoops that provide a snowflake-catching surface. Snowflakes are viewed under a microscope and photographed. (MDH)

Describes how to construct a model of a DNA molecule with inexpensive materials. (BR)

Describes a simple way of obtaining a set of relative intensities of spin-spin splitting lines using Pascal's triangle rather than calculating binomial coefficients. Provides tables showing Pascal's triangle and the relative intensities of multiplets for a range of nuclear spins. (TW)

Describes an experiment in which the beam of X-rays is simulated through the use of a laser as a monochromatic light source and the crystal is replaced by photographically prepared masks. A strong diffraction pattern as large as 20 cm. can be obtained. (GS)

Describes exercises using simple ball and stick models which students with no chemistry background can solve in the context of the original discovery. Examples include the tartaric acid and benzene problems. (GS)

Describes a procedure for teaching the "generator orbital" (GO) approach of molecular orbital bonding in polyatomic molecules. Explains how the GO can be utilized with students in generating the vibrational, rotational, and translational modes of molecules in a completely pictorial manner. (ML)

Thermochemical cycles are used to decide which hypothetical compounds might exist and, if not, what is the factor that condemns them to non-existence. Hypothetical compounds of rare gases provide examples of the approach with added historical interest that thermochemical considerations led to prediction and demonstration that XePtF-6 was stable.…

Discussed are the molecular electronic terms which can arise from a given electronic configuration. Considered are simple cases, molecular states, direct products, closed shells, and open shells. Two examples are provided. (CW)

Describes how to use the distinctive properties of osazone formation in conjunction with molecular model construction to demonstrate the relationship between the three-dimensional structures of simple sugars and the shapes of crystals they form. (BR)