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Transition Metals

Author: Hans Lohninger

The 30 transition metals of period 4 to 6 are hard metals with high melting and boiling points. The atoms tend to become smaller with increasing atomic number across a period because of the increased nuclear charge.

When the 3d transition metals are combined with electronegative elements, the lowest oxidation state in all of them except copper and a few rare compounds of other metals is +2, with both s electrons lost. Other higher oxidation states occur with the loss of more electrons from the d orbitals, up to a maximum equal to the number of unpaired electrons in the d orbitals. This is why the maximum oxidation number increases from + 3 in scandium to +7 in manganese (five d plus two s) and thereafter falls by one per group to + 2 in Zn (loss of only the two s electrons). The most common oxidation states are + 2 and + 3.

Last Update: 2011-02-16