This historical review traces the origins of the Kimball free-cloud model of the chemical bond, otherwise known as the charge-cloud or tangent-sphere model, and the central role it played in attempts to reform the introductory chemical curriculum at both the high school and college levels in the 1960s. It also critically evaluates the limitations…

In response to a reader query, this article traces the history of fusible alloys, including Newton's metal, D'Arcet's metal, Rose's metal, Onion's fusible alloy, and Wood's metal. (Contains 1 table and 1 figure.)

In response to a reader query, this article traces the origins of the ionic-radius ratio rules and their incorrect attribution to Linus Pauling in the chemical literature and to Victor Goldschmidt in the geochemical literature. In actual fact, the ionic-radius ratio rules were first proposed within the context of the coordination chemistry…

The theory of s, p, d and f dealing with the line spectra of the alkali metals during the period 1881 based on analogies with the harmonic ratios of sound is described. Friedrich Hund followed Bohr's practice of labelling the various shells and subshells by replacing the secondary quantum number with the series notations (s, p, d, and f), which…

German Chemist, August Wilhelm Hofmann first introduced the term "molar" (from the Latin moles, meaning "a large mass") into chemistry, around 1865. The particular use of the term molar gained currency in the physics literature, where it was in common use at least through the 1940s.

A question and answer session on whether Lavoisier made an agreement with the French mathematician, Comte Joseph-Louis Lagrange shortly before being beheaded that he would blink his eyes if he retained consciousness after being beheaded and that he was executed because of his revolutionary scientific views is described. The circumstances…

Traces electronegativity in four fundamental areas of chemistry during the period 1870-1910: (1) the relationship between electronegativity and classical valence; (2) the relationship between electronegativity and periodic law; (3) the relationship between electronegativity thermochemistry; and (4) the relationship between electronegativity and…

Investigates the origins of the universal gas constant R and presents an historical perspective. (SOE)

Discusses the origins of electronegativity as a qualitative concept in the period between 1809 and 1813. Outlines the contributions of Amedeo Avogadro and Jons Jakob Berzelius to the development of this concept. Contains 53 references. (JRH)

Presents two illustrations and accompanying text about carbon dioxide toxicity taken from an 1886 textbook. (MLH)

Makes reference to a logic table introduced in the first keynote address of a series of three that focus on the history of chemistry and its application to teaching. Contains 42 references. (DDR)

Discusses major events leading to the development of the octet rule. Three conclusions based on the work of Mendeleev, Abegg, Thompson, Kossel, Lewis, and Langmuir are considered as is the debate over the rule's validity. (JN)

Presents the first of three invited keynote lectures from the 1995 conference of the New England Association of Chemistry Teachers. Discusses the relevance of the history of chemistry to the teaching of chemistry. Contains 27 references. (DDR)