Determination of the actual atomic arrangement in tartaric acid in 1949 motivated a change in stereochemical nomenclature from Fischer's 1891 genealogical convention (D, L) to the CIP scheme (R, S) based on conventional group priorities. Configurational isomers can be interconverted by racemization and epimerization. Pure enantiomers can be separated from racemic mixtures by resolution schemes based on selective crystallization of conglome...more
Professor Sylvia Ceyer discusses the Valence Shell Electron Pair Repulsion (VSEPR) theory and its use with predicting the shapes of individual molecules, based upon their extent of electron-pair electrostatic repulsion. The RSEPR Rules are defined and the shapes based on VSEPR theory rationalized using atomic size and bond length.
Professor Sylvia Ceyer discusses hybridization and chemical bonding. Using methyl nitrate as an example, Professor Ceyer describes how to find the lowest energy Lewis structure and explains bond symmetry, hybrid orbitals, and atomic orbitals. Moving onto intramolecular interactions, the discussion breaks down the origin of a bad hair day: hydrogen bonding, water, and keratin.
Youthful chemists Couper and Kekulé replaced radical and type theories with a new approach involving atomic valence and molecular structure, and based on the tetravalence and self-linking of carbon. Valence structures offered the first explanation for isomerism, and led to the invention of nomenclature, notation, and molecular models closely related to those in use today.
Professor Sylvia Ceyer covers the molecular orbital theory, beginning with a discussion of some key topics including bonding orbitals, antibonding orbitals, electron configurations, and bond order. Using a wealth of examples to depict molecular orbitals (MOs) formed by the linear combination of atomic orbitals (LCAO), she concludes with heteronuclear diatomics.
Professor Sylvia Ceyer devotes this lecture to a discussion of the periodic table, beginning with its history. Period trends are covered, including ionization energy, electron affinity, elecrtonegativity, and atomic sizes. The lecture concludes with isoelectronicity, where two molecular entities have the same number of valence electrons and the same structure, regardless of the nature of the elements involved.
Professor Sylvia Ceyer covers valence bond theory and hybridization in atomic molecules. A number of examples are used to depict sp3 hybridization, sp2 hybridization, and sp hybridization.
Environmental Politics and Law (EVST 255) To illustrate the linkages among national security, secrecy, and environmental quality, Professor Wargo describes the Atomic Energy Commission's nuclear tests in the 1950s. The Atomic Energy Commission collected data on the spread of radionuclides from the nuclear tests, and discovered that the radionuclides were circulating around the world. This process of discovery raised issues regarding wa...more
Electronegativity, metallic nature and atomic radius.