International reserves hold 45% of all gold in the world.All nations still accept it as a medium of exchange today. Gold served as a backing for paper currency in the US from the 19th century all the way up to 1933.Gold does not corrode or tarnish, making it a very durable and thus attractive metal.When flattened, 1 ounce of gold can produce 187 square feet of gold sheets.Gold is the most malleable and ductile element on the periodic table.It has malleable, conductive, and ductile metal properties, and its bright, attractive color makes it a very valuable metal. Video journalist Brady Haran is the man with the camera and the University of Nottingham is the place with the chemists.The element gold is a well-known transition metal with atomic number 79. In this video, we watch several of our favourite chemistry professors as they discuss the wonders of gold and conduct an experiment to gold-plate a cheap casio watch: Their keen interest in this fruitless endeavour provided valuable knowledge for how to identify and work with elements, which in turn, furnished the foundation for modern chemistry. Alchemists famously tried all sorts of crazy experiments designed to transform lead into gold, usually through its interaction with the mythical philosopher's stone. Some other colours include "green gold" (either 75% gold with 25% silver or 73% gold with 27% silver), and "white gold" (gold alloyed with one or more white metals, usually nickel, manganese or palladium).Ĭhemistry owes much to our age-old fascination with gold. In addition to "red gold" (50% gold and 50% copper), and "rose gold" (75% gold with 25% copper), gold alloys range in colour from white to black. For example, copper is the most commonly used base metal, which makes gold appear redder in colour. ( Visit a vault filled with gold bullion at the Bank of England.)Īpproximately half of the world's gold is used in jewelry, although it is typically alloyed with a number of other metals to increase its hardness and to alter its colour. Historically, gold was used as the standard for many currencies around the world and even today, it is stored it in the form of bullion coins or bars in the belief that it can protect its holder against inflation or other economic disruptions. Gold was minted as coins from as early as 700 BC. Further, it has no taste, it provides no nutrition, and it leaves the body unaltered. Yet despite all the hype, metallic gold is inert to all body chemistry. It also is used for gold crowns in dentistry since over the long term, gold's malleability makes it less damaging than porcelain crowns to the grinding surface of molars.Īt one time, consuming gold was erroneously thought to be beneficial for health (and still is, in some circles). However, it is used in research and medicine, especially as a thin coating for biological specimens viewed by scanning electron microscopy. Gold is of limited interest to biologists since it is not essential for life. In fact, only one other elemental metal is yellow or gold-coloured cæsium, and its colour is the result of similar effects. This distinctive colour results from the oscillations of its loosely bound outer (valence) electrons. Unusual amongst elemental metals, which are either grey or white in colour, gold is bright yellow. Occasionally, gold occurs as a compound in minerals, usually with tellurium. In the wild, gold occurs most often in its pure elemental form as either nuggets, or as grains or veins in rock and in alluvial deposits. Besides being beautiful, gold is very useful because it is resistant to corrosion and to most chemical reactions, and it is the most malleable and ductile of all metals. As its name implies, gold is a lustrous yellow in colour.
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