![]() And some or all of the metalloids may or may not be included in the applicable sections.Ī richer, complementary taxonomy is introduced in this article. Thus, in a textbook, there may be separate sections on hydrogen carbon nitrogen and phosphorus and oxygen, sulfur, and selenium. In Steudel’s Chemistry of the nonmetals (1977, preface)Īfter highlighting the halogens and the noble gases, authors have always found it difficult to treat the remaining nonmetals on a holistic rather than group-by-group basis. “The marvellous variety and infinite subtlety of the non-metallic elements, their compounds, structures and reactions, is not sufficiently acknowledged in the current teaching of chemistry.” The literature is sparse when it comes to holistic treatments of their chemistry. Wikipedia ( 2019a) records 15 different category names for these elements located between the transition metals and the metalloids, including ‘other metals’. In some respects, the frontier metals can be regarded as the forgotten metals. Being adjacent to the non-metals, their crystalline structures tend to show covalent or directional bonding effects, having generally greater complexity or fewer nearest neighbours than other metallic elements (Russell and Lee 2010, p. A minority are moderately electropositive (zinc, for example) (Kneen et al. Most of them, such as tin and bismuth, are chemically weak. The frontier metals, as a class, are adjacent to the dividing line between metals and nonmetals. A small number, such as zirconium, are more strongly electropositive several others are chemically very weak (or noble), like platinum, with these representing the noble metals. The transition metals are, for the most part, moderately to weakly electropositive in nature (Kneen et al. They are mostly strongly electropositive metals, with a few of the light actinoids (uranium to americium) being only moderately electropositive. The active metals are here considered to encompass groups 1–3, the lanthanoids and actinoids, and aluminium in group 3. Footnote 1 A fourth class, the noble metals, is a subset of the transition metals (MacKay et al. The metals can be divided into broad classes, as: active metals transition metals and frontier metals (Russell and Lee 2005, p. A few borderline elements are sometimes identified as metalloids. In general, the elements of the periodic table can be divided into metals and nonmetals.
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