The formulation of the periodic system by the Russian Mendeleev was followed by the surprising discovery of gallium by the Frenchman de Boisbaudran. The Englishman Ramsay's explanation of an 'impurity' in air led to recognition of a new period. A young fellow countryman, Moseley, justified the expected existence of 92 elements. A German couple,…

Using the layout described here (which could be photocopied or handwritten), students can see how the periodic table was first envisaged after finding similarities in the properties of common elements. Then, with more discoveries some gaps were filled and, when additional elements did not fit, new groups had to be included.

Rheology is an enormously far-reaching branch of physics (or physical chemistry) and has a number of different guises. Rheological descriptions define fluids, semi-solids and conventional solids, and the application of this science defines the performance and utility of materials and substances as diverse as foods (such as yogurt and marmalade),…

This article aims to introduce the lanthanides (also known as the lanthanoids) to teachers and their students. The lanthanides are not mere "footnotes" at the bottom of the periodic table but make up a group of interesting and unique metallic elements. They and their compounds have widespread technological applications that have become…

Revision can be a rather dull part of the academic year, especially if it means the wholesale revisiting of the syllabus using the same old notes. This article presents an attempt at using the "biography" of an element to give an alternative framework for recapping some of the key concepts in a typical A-level chemistry syllabus. It does…

In 1984, a teacher was successfully prosecuted by the Health and Safety Executive. The case centred around chemically prepared hydrogen that was dried by bubbling it through concentrated sulfuric(VI) acid and then passed over hot copper(II) oxide. The procedure was often carried out quantitatively to find the mass of copper in a sample of…

This article provides an example of a teacher's learning, since the author only became aware of the microscale technique described very late in his professional career. The technique provides a convenient method of preparing and manipulating gases on a very small scale and a relatively safe means of demonstrating reactions that would be very…

Describes how some of the Theory of Knowledge (ToK) requirements, which is a central part of the International Baccalaurate (IB) Diploma program, for the natural sciences component can be addressed through case studies from the history of chemistry and related subjects. Provides examples for the 'Ideas and evidence in science' which can be useful…