How is gold a transition metal

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Area of ‚Äč‚ÄčExpertise - General Chemistry

To the group of Transition metals or. Transition elements count according to the IUPAC definition elements of the periodic table, the atoms of which are only partially occupied by electrons d-Shell or cations with incompletely filled d-Shell can form. Since these elements are all metals, these elements become Transition metals called.

Tab. 1
The following elements belong to the transition metals:
Period of the PSEelementsOrdinal numbers
4Scandium to copper21-29
5Yttrium to silver39-47
6Lanthanum to gold, lanthanides57-79
7Actinium, actinoids, transactinoids89-111

To further differentiate the element group, there is usually a subdivision into outer transition elements (d block elements, in which the second outermost shell is filled with electrons) and the inner transition elements(Lanthanoids and Actinides) (f-block elementsin which the third outermost electron shell is occupied).

Deviating from the IUPAC definition, the elements with completely filled d-Shells (d10-Elements: zinc, cadmium, mercury, element 112) counted among the transition metals. In this combination, the transition elements correspond to the previous designation Subgroup elements.

All transition elements have typical metallic properties, e.g. good conductivity for heat and electricity as well as metallic sheen. They generally have a high density and a high melting point and magnetic properties. Since the electronic configuration of the outer shell is particularly important for the chemical properties of an element, the transition metals within a period - in which only inner shells are filled - do not differ as clearly from one another as the elements of other groups. Some of the elements that are very similar in their behavior are grouped together in certain sub-groups (platinum metals, rare earth metals).

Transition metals can by donating electrons from the outside s- and the d-The level of their chemical compounds have oxidation states between +1 and +8. In special cases they are incompletely filled due to the uptake of electrons d-Peel also possible negative oxidation states. The oxidation state +2, which results from the release of the two, is particularly common with the outer transition elements s-Electrons in the outermost electron shell yields (e.g.,,). Also oxidation numbers that are half or fully occupied d-Level are particularly stable, such as,,. Inner transition metals form by releasing the two outer ones s-Electrons as well as another, underlying electron, predominantly trivalent cations.

A characteristic of transition metals is the often intense color of their compounds, which changes with the oxidation level.

The slight change in the oxidation state and a pronounced tendency towards the formation of complex compounds make many transition metals an indispensable component in technically important catalyst systems, e.g. iron acts as a catalyst in the Haber-Bosch process for the synthesis of ammonia. A large number of organic substances can be hydrogenated, oxidized or polymerized in a targeted manner using homogeneous or heterogeneous catalysis (e.g. olefin polymerization using Ziegler-Natta catalysts). In biological systems, complex bound transition metals are used, among other things, for nitrogen fixation or oxygen transfer (see hemoglobin).

See also: electron configuration