Gold (Au). The symbol for gold on the periodic table is ‘Au’. Gold. The discoverer of gold is unknown. Although it is believed to have been discovered around 3000BC. This precious metal has been highly sought after for many centuries. Gold has the appearance of
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The symbol for gold on the periodic table is ‘Au’.
Uses for Gold
Other Uses of Gold
Gold-198 is a radioactive isotope of gold. It is used for treating cancer.
Gold sodium thiosulfate (AuNa3O6S4) is used for the treatment of arthritis.
Chlorauric acid (HAuCl4) is used to preserve photographs by replacing the silver atoms present in an image.
Pure gold is referred to as ‘24 carat’ gold. It is often alloyed with silver and copper.
24 carat - 100% gold.
18 carat - 75% gold + 25% silver and/or copper.
9 carat - 37.5% gold + 62.5% silver and/or copper.
Major Steps in Extraction of Gold from its ore.
Host rock and specks of gold.
Concentrated gold ore.
Add zinc or electrolysis
Extraction of Gold using Cyanide
4Au (s) + 8CN- (aq) + 2H2O (l) + O2(g)
4Au(CN)2- (aq) + 4OH- (aq)
The Au(CN)2- is separated from the pulp using activated carbon. The gold is then recovered by adding zinc (metal ion displacement) or by electrolysis.
The properties of gold give it the ability to be beaten into sheets no thicker than 0.00001 mm or 400 times thinner than a human hair.
The fact that gold is so malleable and ductile one gram of it can be beaten into a one square metre sheet.
History of Gold
Since prehistoric times, gold has been known about and highly valued.
Gold is used to symbolise purity, value and royalty. It is also a sign of wealth.
Gold can be found freely in nature, however it is usually found in silver, quartz, lead, zinc or copper.