Gold

Gold (pronounced /ˈɡoʊld/) is a chemical element with the symbol Au (Latin: aurum, "shining dawn") and an atomic number of 79. It has been a highly sought-after precious metal for coinage, jewelry, and other arts since the beginning of recorded history. The metal occurs as nuggets or grains in rocks, in veins and in alluvial deposits. Gold is dense, soft, shiny and the most malleable and ductile pure metal known. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Gold is one of the coinage metals and has served as a symbol of wealth and a store of value throughout history. Gold standards have provided a basis for monetary policies. It also has been linked to a variety of symbolisms and ideologies.

A total of 161,000 tonnes of gold have been mined in human history, as of 2009.^[1] This is roughly equivalent to 5.175 billion troy ounces or, in terms of volume, about 8,333 cubic meters, and, without accounting for the enormous increase in supply, could be valued at just under six trillion United States dollars at early March 2010 prices.

Although primarily used as a store of value, gold has many modern industrial uses including dentistry and electronics. Gold has traditionally found use because of its good resistance to

General properties
Name, symbol, number	gold, Au, 79
Element category	transition metal
Group, period, block	11, 6, d
Standard atomic weight	196.966569(4) g·mol−1
Electron configuration	[Xe] 4f14 5d10 6s1
Electrons per shell	2, 8, 18, 32, 18, 1 (Image)

oxidative corrosion and excellent quality as a conductor of electricity.

Chemically, gold is a transition metal and can form trivalent and univalent cations in solutions. Compared with other metals, pure gold is chemically least reactive, but it is attacked by aqua regia (a mixture of acids), forming chloroauric acid, but not by the individual acids, and by alkaline solutions of cyanide. Gold dissolves in mercury, forming amalgam alloys, but does not react with it. Gold is insoluble in nitric acid, which dissolves silver and base metals. This property is exploited in the gold refining technique known as "inquartation and parting". Nitric acid has long been used to confirm the presence of gold in items, and this is the origin of the colloquial term "acid test", referring to a gold standard test for genuine value.