Valence shell electron pair repulsion theory (VSEPR) as explained in most textbooks predicts that substituents bonded to a central atom in AX[subscript n]E[subscript z][superscript c] species (A = main-group central atom, X = substituent, E = lone pair on central atom, c = charge) will change their X-A-X angles to bend away from the lone pairs.…

This review describes a computational chemistry exercise aimed at enhancing the understanding of upper-division undergraduates in organic chemistry and physical chemistry regarding the structures and aromaticities of cyclobutadiene and cyclooctatetraene. This exercise exposes students to chemical problems that require computational methods as a…

The fundamental mechanism of biochemistry lies on the reaction kinetics, which is determined by the reaction pathways. Interestingly, the reaction pathway is a challenging concept for undergraduate students. Experimentally, it is difficult to observe, and theoretically, it requires some degree of physics knowledge, namely statistical and quantum…

The concept of an atom with an expanded octet, known as hypervalency, has persisted in the general chemistry curriculum, despite abundant theoretical work disputing its veracity. Here, the electronic structure of traditionally hypervalent molecules (H[subscript 2]SO[subscript 3], H[subscript 2]SO[subscript 4], PF[subscript 5], and SF[subscript 6])…

Modeling an inter-ring torsional profile of a simple2,2'-bithiophenemolecule has been used to illustrate the main concepts associated with basic molecular modeling within an introductory course in a master's degree on computational modeling. The methodology proposed in the activity has been used to guide and train the student along the classical…

An instructional approach is presented for teaching the mole concept to high school introductory-level chemistry classes. Extensions to the strategy are presented for more advanced classes. The strength of the approach is based upon discovery. Students discover the Avogadro number and the mole concept. The discovery is based upon calculations that…

The aim of this article is to present a set of simple exercises that help the students of a second course in quantum chemistry to understand that some molecular properties do not improve even when the molecular energy improves with an increasing number of basis functions in the expansion of the wavefunction. The essential idea is to create a…

An introduction to the Quantum Chemistry Package (QCP), implemented in the computer algebra system Maple, is presented. The QCP combines sophisticated electronic structure methods and Maple's easy-to-use graphical interface to enable computation and visualization of the electronic energies and properties of molecules. Here we describe how the QCP…

Integrating knowledge across disciplines has been shown to be a challenging, and yet it is a necessary skill that university students need to develop. Students who are able to connect different concepts, perspectives, and angles of a given topic are generally more engaged and have better understanding. However, designing lesson plans or…

A computational laboratory experiment investigating molecular models for hexagonal boron-carbon-nitrogen sheets (h-BCN) was developed and employed in an upper-level undergraduate chemistry course. Students used the Avogadro user interface for molecular editing and the WebMO interface for the quantum computational workflow. Density functional…

In this work, two exercises are described that are designed to teach students about the evolution and behavior of the electronic bands of graphene and bilayer graphene. These exercises involve performing extended Hückel molecular orbital theory calculations on polyacenes and polycyclic aromatic hydrocarbons. In the first exercise, students…

Activation energies form an energy barrier to a chemical reaction taking place. Simple collision theory, i.e. that particles need to collide to react, would suggest that activation energy is the energy needed to overcome a coulombic barrier provided by the negatively charged electrons contained within energy shells surrounding an atomic nucleus.…

This two-period undergraduate laboratory experiment involves the synthesis of a mixture of isomeric unknowns, isolation of the mixture by means of distillation, and characterization of the two products primarily by NMR spectroscopy (1D and 2D) supported with IR spectroscopy and GC-MS techniques. Subsequent calculation and examination of the…

The "Yet Another extended Hu¨ckel Molecular Orbital Package" (YAeHMOP) has been merged with the Avogadro open-source molecular editor and visualizer. It is now possible to perform YAeHMOP calculations directly from the Avogadro graphical user interface for materials that are periodic in one, two, or three dimensions, and to visualize…

A laboratory project for the upper-division physical chemistry laboratory is described, and it combines IR and Raman spectroscopies with Gaussian electronic structure calculations to determine the structure of the oxalate anion in solid alkali oxalates and in aqueous solution. The oxalate anion has two limiting structures whose vibrational spectra…