Describes an undergraduate laboratory experiment on the statistical theory of nuclear reactions. The experiment involves measuring the relative cross sections for formation of a nucleus in its meta stable excited state and its ground state by applying gamma-ray spectroscopy to an irradiated sample. Involves 3-4 hours of laboratory time plus…

Provides the rationale for and examples of experiments designed to test the stability of protons and bound neutrons. Also considers the unification question, cosmological implications, current and future detectors, and current status of knowledge on proton decay. (JN)

Presents suggestions for alternative presentations of some of the material that usually forms part of the introductory chemistry course. Emphasizes development of concepts from experimental results. Discusses electronic configurations and quantum numbers, experimental evidence for electron configurations, deducing the shell model from the periodic…

Surveys new laser techniques and a variety of spectroscopic experiments that can be used to detect, measure and study very small numbers of atoms on molecules. The range of applicability of these techniques is also included. (HM)

Flame tests are used for demonstration of atomic structure. Describes a demonstration that uses spray bottles filled with methanol and a variety of salts to produce a brilliantly colored flame. (Contains 11 references.) (ASK)

Electrochemiluminescence involves the production of light near an electrode surface by generating species that can undergo highly energetic electron transfer reactions. Presents a demonstration that uses Ru(bpy)32+ (bpy = 2,2'-bipyridine) as the light-emitting molecule and tri-n-propylamine (C9H21N) as a coreactant. (Contains 25 references.) (ASK)

Describes the theory and application of an atomic fountain which pushes the atoms by laser pulses. Discusses the applications in measuring atomic properties and in building an atomic clock. (YP)

Presents an alternative approach to bonding and geometry--the electron domain model--which avoids some of the problems with the conventional approach. Discusses difficulties with the orbital model at the introductory level, electron spin and the Pauli exclusion principle, electron pair domains, nonequivalent domains, multiple bonds, and origins…

Shows how ionization energies provide a convenient method for obtaining electronegativity values that is simpler than the conventional methods. Demonstrates how approximate atomic charges can be calculated for polar molecules and how this method of determining electronegativities may lead to deeper insights than are typically possible for the…

Describes the use of atomic spectra that are excited in inductively coupled plasmas for the simultaneous or sequential determination of the elements at all concentration levels. (HM)

Discusses the development of the concept of atomicity and some of the many which can be used to establish its validity. Chemical evidence, evidence from crystals, Faraday's law of electrolysis, and Avogadro's number are among the areas which show how the concept originally developed from a purely philosophical idea. (JN)

Discusses student use of the computer with mathematical models and with laboratory simulations. Examples given. (DS)

Describes activities (demonstrations/experiments) used to introduce history of periodic properties--without electrons, orbitals, filling shells, or any conception of atoms beyond Dalton's model. Activities supplement first chapter in a currently available chemistry text. Indicates potential danger of experiments if proper safety precautions are…

Clarifies misunderstanding of Millikan's experiment measuring charge on electrons. Most books describing the experiment indicate ionization of air in the apparatus caused liberation of electrons, and that these electrons were picked up by oil droplets. However, in Millikan's discussion, it is stated clearly that ions were attached to oil droplets.…