d-Block: the transition metals

Abstract

In the previous two chapters the chemistry of the forty-three main group elements has been outlined. The underlying principle to their chemistry is the filling of s and p subshells with consequent changes in ionisation energy and many other related properties. Between the alkaline earth elements of group IIa and the elements of group IIIb lie ten other groups of elements, corresponding to the filling of d subshells. These thirty elements are called transition metals, and although we shall only make a brief survey of their chemistry, some of them, such as iron, copper, and zinc, are of fundamental importance to our civilisation. The elements fall into groups based on their nuclear charge, etc., but family relationships within a group in the d block are often less marked than the general similarities between an element and its horizontal neighbours, and the general similarities of all the transition elements. This is least true for the first and last groups, IIIa and IIb, which show strong family similarities. Group VIIIa has three members from each period: this anomaly has arisen because the periodic table was not constructed on the basis of orbital filling, but on the basis of numerical theories such as Newland’s sevens (see section 18.2). Because this chapter makes only a brief survey of the transition metals, rather than summarising the chemistry of each group, the main trends will be picked out, and illustrated, after which more details will be given of some of the more important members.