Overgangsmetallen

Overgangsmetallen, also known as transition metals, are a group of chemical elements found in the d-block of the periodic table. They are characterized by having incompletely filled d subshells, either in their elemental form or in their common oxidation states. This electron configuration gives rise to many of their distinctive properties.

The transition metals include elements from Groups 3 through 12 of the periodic table. Common examples are iron, copper, gold, silver, and platinum. Unlike the alkali and alkaline earth metals of the s-block, transition metals are generally harder, have higher melting and boiling points, and are less reactive. They are typically good conductors of heat and electricity.

A key characteristic of transition metals is their ability to form colored compounds. This is due to the d-electrons absorbing certain wavelengths of visible light, resulting in the transmission or reflection of complementary colors. Furthermore, many transition metals exhibit variable oxidation states, meaning they can lose a different number of electrons in chemical reactions. This versatility contributes to their widespread use in catalysis, where they can facilitate chemical transformations.

Transition metals also readily form complex ions, where a central metal atom or ion is bonded to a surrounding group of molecules or ions called ligands. These complexes are important in various biological processes, such as the transport of oxygen by iron in hemoglobin and the catalytic activity of enzymes containing metals like zinc and copper. Their unique chemical and physical properties make them indispensable in numerous industrial applications, including the production of alloys, electronics, and pharmaceuticals.