A knowledge of ionisation energies helps us understand the elements and their chemistry. The usual plots of first ionisation energies give us little insight. Apparent irregularity of first and second ionisation energies of transition metals and lanthanides can be explained in terms of the electronic configurations of the ground states. Periodicity…

This article offers a concise account of the known science underpinning the greenhouse effect and global warming. The greenhouse effect is described at different levels of sophistication. It explains how greenhouse gases work and their relative contribution to warming. Climate models are introduced, as are climate sensitivity, feedback mechanisms…

The mathematical method of linear equations involving the coefficients of the equation of a chemical reaction can be used to balance the equation of nearly every chemical reaction. For its application, only the rules of simple algebra need be known. Hence, the method could even be used by students of an elementary chemistry course.

O•, O[subscript 2] and O[subscript 3] play vital roles in the Earth's atmosphere, regulating ultraviolet radiation from the Sun and being essential for life. However, the oxygen family, O•, O[subscript 2] and O[subscript 3], also provides a source of the HO radical, the atmospheric detergent that removes pollutants from the atmosphere. This…

Potassium is the main intracellular ion in prokaryotic and eukaryotic cells and is essential for their functions, making potassium one of the most important electrolytes in physiology. In humans, potassium plays a vital role in several physiological functions, including the maintenance of fluid balance, generating the membrane potential of cells,…

Society at large often incorrectly thinks that the word 'chemicals' implies danger, when of course all matter can be described as a chemical. In this article we define what precisely we mean by 'hazard', risk' and 'danger'; we then consider selected elements from the periodic table that are noteworthy because of their dangerous characteristics.

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,…

In this article we describe a demonstration for most of the elements from the periodic table which together constitute the show "An Elemental Spectacle: A Guided Tour of the Darker Reaches of the Periodic Table."

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.

Every day we deal with chemistry in various forms, but sometimes we don't see that. An example is biosensors that help us to evaluate health conditions, monitor environmental pollution and ensure food freshness. The most well known (and most widely sold) is the biosensor for blood glucose measurement, used every day by people with diabetes.…

An introduction to the noble gases and chemical bonding via Lewis theory and the octet rule are common inclusions in secondary school curricula. However, the usual approach may lead to misconceptions and difficulties when valence bond (VB) theory and valence shell electron pair repulsion (VSEPR) theory are taught at a later pre-university stage.…

Should entropy and energy be emphasised as relevant concepts for biology education? This question will be discussed, highlighting the ways in which the concepts of entropy and energy can contribute to a better understanding of biological processes. Organisms are open systems. Therefore, the chosen perspective is different from the traditional…

This article aims to introduce the actinides and some aspects of nuclear chemistry to teachers and their students. The actinides are a group of f-block elements with atomic numbers from 90 to 103. (The term 'actinoids' encompasses both the actinides and actinium itself). All of the actinides are radioactive but they also have a rich inorganic…

Many teachers do not notice, or do not understand, the chemistry going on in and around their homes and hence do not point it out to their students. Thus they miss out on an important motivating experience. This article gives a few random examples, most of them well within the understanding of students at key stages 3 and 4 (age 11-16). From…

This article argues that we need to make use of our everyday experiences when introducing concepts in chemistry that are often obscure. It uses reaction rates as an example and explores a common misconception related to the explanation of the effect of rising temperature on the rate of slow reactions.