Gold
hideGold (pronounced /ˈɡoʊld/) is a chemical element with the symbol Au (Latin: aurum) and an atomic number of 79. It has been a highly sought-after precious metal in jewelry, in sculpture, and for ornamentation 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. It is one of the coinage metals and formed the basis for the gold standard used before the collapse of the Bretton Woods system in 1971.
At the end of 2006, it was estimated that all the gold ever mined totaled 158,000 tonnes. This can be represented by a cube with an edge length of just 20.2 meters. Modern industrial uses include dentistry and electronics, where gold has traditionally found use because of its good resistance to oxidative corrosion and excellent quality as a conductor of electricity. Chemically, gold is a transition metal and can form trivalent and univalent cations upon solvation. At STP it is attacked by aqua regia (a mixture of acids), forming chloroauric acid and by alkaline solutions of cyanide but not by single acids such as hydrochloric, nitric or sulfuric acids. Gold dissolves in mercury, forming amalgam alloys, but does not react with it. Since gold is insoluble in nitric acid which will dissolve silver and base metals, this is exploited as the basis of 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.
For more information about Gold, read the full article at
Wikipedia.
This text uses material from Wikipedia and is available under the GNU Free Documentation License.
News tagged with gold
Gene Testing In the Doctors Office
Nanotechnology / Bio & Medicine
Dec 02, 2009 |
5 / 5 (4) |
0
(PhysOrg.com) -- A portable instrument manufactured by Nanosphere Inc. and recently approved by the FDA, can detect genetic variations in blood that alter the effectiveness of some drugs.
Fast, easy, and highly sensitive arsenic detection with gold nanoparticles
Nanotechnology / Nanomaterials
Nov 25, 2009 |
5 / 5 (1) |
0
(PhysOrg.com) -- Mention of arsenic poisoning usually brings to mind underhanded murder. However, the danger of arsenic poisoning from contaminated drinking water is far greater. Low concentrations of arsenic are found in ...
Highlight: Damping of acoustic vibrations in gold nanoparticles
Nov 19, 2009 |
4 / 5 (2) |
0
Vibrations in nanostructures offer applications in molecular-scale biological sensing and ultrasensitive mass detection. To approach single-atom sensing, it is necessary to reduce the dimensions of the structures ...
Search results for gold
Wizard at circuits, physics
23 hours ago |
5 / 5 (10) |
0
(PhysOrg.com) -- Donhee Ham, Gordon McKay Professor of Electrical Engineering and Applied Physics, uses his personal energy and understanding of physics to design innovative integrated circuits.
Samsung Announces the Premium I8910 HD Gold Edition
Electronics / Consumer & Gadgets
Dec 03, 2009 |
1 / 5 (1) |
0
Samsung Electronics today announced the availability of the I8910 HD (Omnia HD, GT-I8910) Gold Edition. This premium version of the ground-breaking full touch screen smartphone features a luxurious new look ...
Google, other Silicon Valley firms nurture app developers
Dec 03, 2009 |
3 / 5 (1) |
0
They crowd the lobby of Google's Building 43 one evening a month, waiting to climb the wide stairway under a mock-up of the world's first private spacecraft, SpaceShipOne, prepared to delve deep into the Internet giant's ...
Gift Guide: A focus on HD video, at many prices
Electronics / Consumer & Gadgets
Dec 01, 2009 |
not rated yet |
0
It's easier than ever to shoot high-definition video. You can do it with traditional-style camcorders, of course, but also with cameras that also are designed to take still photos - from high-end "digital ...
First Step To Success steps up in Albuquerque schools
Medicine & Health / Psychology & Psychiatry
Nov 30, 2009 |
5 / 5 (1) |
0
A school-based behavioral intervention program developed under a federal grant in the mid-1990s at the University of Oregon, already in widespread use, now has shown real value on a complex stage, scoring ...
Fujitsu Develops Technology for Low-Temperature Full-Service Direct Formation of Graphene Transistors on Large-Scale Sub
Nov 27, 2009 |
5 / 5 (20) |
4
Fujitsu Laboratories today announced, as a world first, the development of a novel technology for forming graphene transistors directly on the entire surface of large-scale insulating substrates at low temperatures ...
In Greenland, warming fuels dream of hidden wealth
Nov 27, 2009 |
3.5 / 5 (4) |
1
(AP) -- Gert Ignatiussen returns to this fjord-front Inuit town with the spoils of his hunting trip. Six seals, all killed with a single shot to the head.
Nanowires key to future transistors, electronics
Nov 26, 2009 |
4.5 / 5 (10) |
2
(PhysOrg.com) -- A new generation of ultrasmall transistors and more powerful computer chips using tiny structures called semiconducting nanowires are closer to reality after a key discovery by researchers ...
Exposure to lead, tobacco smoke raises risk of ADHD
Nov 23, 2009 |
not rated yet |
0
Children exposed prenatally to tobacco smoke and during childhood to lead face a particularly high risk for ADHD, according to research done at Cincinnati Children's Hospital Medical Center.
A Tiny Cage of Gold Responds to Light, Opening to Empty Its Contents
Nanotechnology / Bio & Medicine
Nov 19, 2009 |
5 / 5 (3) |
0
(PhysOrg.com) -- Researchers at Washington University in St. Louis have developed a polymer-coated gold nanocage that not only opens in response to light to release a small amount of a drug payload, but then closes when the ...
List of search results for gold
