transition series metals (main)

The first three periods of the elements in groups 4 through 11—titanium through copper, zirconium through silver, and hafnium through gold—are considered the main transition elements, or transition metals (the lanthanons and actinons, treated elsewhere, are sometimes called inner transition series elements). All are metals; most of them are hard, strong, and lustrous, have high melting and boiling points, and are good conductors of heat and electricity. Many of the elements are technologically important and form many useful alloys, with one another and with other metallic elements. Most of these metals dissolve in mineral acids, although a few, such as platinum, silver, and gold, are called "noble"—that is, are unaffected by simple (nonoxidizing) acids. All the elements of the main transition series exhibit variable valence and form stable compounds in two or more formal oxidation states. All exhibit an unfilled outer d-electron shell, although not all d-block metals are members of this group. D-block elements scandium, yttrium, lanthanum, for example, behave more like the rare earth lanthanons, with whom their chemistry is quite homologous, and actually do not form compounds analogous to those of the other transition elements. Similarly, the d-block zinc metals of group 12—zinc, cadmium, and mercury—exhibit few of the properties characteristic of the other transition elements, and are treated as a separate class of metals. For more detail on the three main transition series, the actinons, and the lanthanons, see the menu item SERIES. For more detail on the zinc metals and other families, see the menu item GROUPS.