Gold is a chemical element with the symbol Au and atomic number 79. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal in pure form. Here are some key properties and uses of gold:
Properties:
- Gold is a transition metal and a group 11 element.
- It is one of the least reactive chemical elements and is solid under standard conditions.
- Gold is chemically unreactive, although it will dissolve in aqua regia (a mixture of nitric and hydrochloric acids).
- It is a soft metal with a characteristic yellow color.
- Gold is malleable and shiny, making it a good metalworking material.
- It is conductive, which makes it useful in electronics.
Uses:
- Gold is a precious metal that has been used for coinage, jewelry, and other arts throughout recorded history.
- It is used extensively in jewelry, either in its pure form or as an alloy.
- The term ‘carat’ indicates the amount of gold present in an alloy. 24-carat is pure gold, but it is very soft. 18- and 9-carat gold alloys are commonly used because they are more durable.
- Most mined gold is stored as bullion.
- Gold has been used to treat cancer in recent decades.
- It is used in astronaut helmets to block harmful ultraviolet rays from the sun.
Gold is found in ores in rock formed from the Precambrian time onward. It most often occurs as a native metal, typically in a metal solid solution with silver (i.e. as a gold/silver alloy). Such alloys usually have a silver content of 8–10%. Electrum is elemental gold with more than 20% silver, and is commonly known as white gold. Gold is one of the few elements to occur in a natural state. About 1500 tonnes of gold are mined each year, with most of it coming from South Africa and Russia. Seawater contains about 4 grams of gold in 1,000,000 tonnes of water, but attempts to reclaim this gold have always failed due to the low concentration.
