Group 11
From Halbeeg, the open encyclopedia · Af-Soomaali
59 languages
Group 11 is one of the columns of the periodic table of elements. It contains copper (Cu, atomic number 29), silver (Ag, 47), gold (Au, 79), and roentgenium (Rg, 111), a synthetic element produced in laboratories. The first three are transition metals.
An alternative name is "group 11 elements." Copper, silver, and gold were historically called the "coinage metals" because metallic coins were made from them for long periods. In earlier nomenclature systems, this group was designated IB.
Electronic structure
Elements in this group have an electron configuration ending in (n−1)d10 ns1—a filled d subshell with a single electron in the outer s orbital. Because only one electron occupies the outer shell, they show properties similar to those of group 1 (alkali metals) in the +1 oxidation state. However, the filled d subshell imparts additional properties: they are hard, conduct heat and electricity well, and show much lower chemical reactivity compared to the alkali metals.
Chemical properties
Copper commonly exhibits oxidation states of +1 and +2; silver mainly +1; gold +1 and +3. The increased stability of higher oxidation states in gold is related to relativistic effects acting on electrons in heavy atoms. The color of gold (yellow) and the instability of some of its compounds are likewise attributed to these effects.
All three metals show resistance to corrosion compared to other metals. Gold in particular does not react with common acids, though it can be dissolved in aqua regia. Silver reacts with sulfur-containing substances, producing a dark tarnish on the surface.
Uses and occurrence
Copper is widely used in electrical wiring, water pipes, and alloys such as bronze and brass. Silver is used in electrical components, mirrors, and historically in chemical photography. Gold is used as a store of value, jewelry, and electrical contacts, because of its corrosion resistance.