Although instruction on meiosis is repeated many times during the undergraduate curriculum, many students show poor comprehension even as upper-level biology majors. We propose that the difficulty lies in the complexity of understanding DNA, which we explain through a new model, the DNA triangle. The "DNA triangle" integrates three…

Focuses on a recent approach to chirality that seeks to call attention to the fact that current usage of this term is often inconsistent with its proper relationship to molecular structure. (TW)

Investigated use of overhead transparencies containing a sequence of diagrams to represent a three-dimensional structure at different stages during a rotation. Significant learning occurred among 120 Bahraini boys (aged 15-16) when the transparencies contained multi-colored diagrams which were exposed simultaneously or individually in a cumulative…

Advocates the teaching of quantum chemical ideas to undergraduates. Discusses the total failure of the electronegativity approach and comparison with other theoretical approaches. (CW)

Describes a simple method to teach molecular geometry using styrofoam balls and velcro strips. Discusses the construction and a procedure for using the model for teaching. (CW)

Provides an introduction to and summaries of the manufacturing methods and uses of chemicals 51-75 on the list of chemicals arranged in order of decreasing production in the United States. Gives production in pounds, annual growth, average price per pound, and organization according to the seven basic organic chemicals. (CW)

Presents calculations that suggest stoichiometric, ionic, and noble gas-metal compounds may be stable. Bases calculations on estimated values of electron affinity, anionic radius for the noble gases and for the Born exponents of resulting crystals. Suggests the desirability of experiments designed to prepare compounds containing anionic,…

Discusses the significance of periodicity and covalent atomic radius among the elements. Describes contraction across the row, expansion down the group, irregularities in the buildup of the periodic table and periodicities of physiochemical properties. (CW)

Discusses the variety of explanations in organic chemistry textbooks of a physical property of organic compounds. Focuses on those concepts explaining attractive forces between molecules. Concludes that induction interactions play a major role in alkyl halides and other polar organic molecules and should be given wider exposure in chemistry texts.…

Presents coulombic models representing the particles of a system by point charges interacting through Coulomb's law to explain coulombic lattice potential. Uses rubidium manganese trifluoride as an example of cubic perovskite structure. Discusses the effects on cluster properties. (CW)

Proposed is a more didactic version of the electronic periodic table than is being used. The background and use of the numeric system is detailed and illustrated. (CW)

Gives the background history of the simultaneous discovery of acid-base relationships by Johannes Bronsted and Thomas Lowry. Provides a brief biographical sketch of each. Discusses their concept of acids and bases in some detail. (CW)

This review is divided into the following analytical methods: ion spectroscopy, electron spectroscopy, scanning tunneling microscopy, atomic force microscopy, optical spectroscopy, desorption techniques, and X-ray techniques. (MVL)

Reports on a study into the relationship between a student's ability to solve problems in chemistry and his/her understanding of molecular concepts. Argues that teaching students to solve problems about chemistry is not equivalent to teaching about the nature of matter. (TW)

Described is a method that can be used to obtain molecular or atomic term symbols. Several examples accompany an explanation of the method. (CW)