Periodic Table -> Gold


Gold Details

Gold Symbol: Au

Gold Atomic Number: 79

Gold Atomic Weight: 196.96655

What is Gold?

Gold (symbol Au, atomic number 79) has it's name from the Latin "Aurum", which means shining dawn. What formed this association is not known, because gold has been known to man since antiquity or about 5,500 years. Perhaps the lustrous, shiny, and attractive metal was found by someone early in the morning glittering somewhere and this person, enticed by what they saw, gave it this name. This is a pity, because "why is gold Au and not G" is the standard question of chemistry students, who are baffled by the odd symbol and even more baffled by what Aurum could possibly mean.

While gold occurs independently of other metals, most often it is mined in conjunction with copper, zinc, lead, silver, and tellurium. One ton of seawater contains about one milligram of gold but extraction is more expensive than what the gold is worth.

Pure, 24-karat gold is bright yellow in color and extremely malleable, so that it is impossible to make anything out of it. This comes as a great disappointment to rich but stupid people who want jewelry made of pure gold. It is alloyed with metals like palladium, platinum, and copper as to increase its strength.

Gold does not lose its bright color, because it does not oxidize in air or water. Gold is one of the group 11 elements, the others being silver and copper. It is among the least reactive solid elements in the periodic table. This is why gold is found naturally in the environment in rocks, alluvial deposits and veins. Sometimes it is also found as a compound with the element tellurium in minerals.

Gold can be dissolved by nitro-hydrochloric acid. It dissolves in cyanide’s alkaline solutions and in mercury. Nitric acid dissolves silver but gold is insoluble in it, which is why nitric acid is used to prove the presence of gold in various items.

Ever since gold has been known to man, 165,000 tons of it has been mined. The biggest portion of gold is used to make jewelry. A little less than this amount serves as investments, and a small part is used in industry. The metal is a good conductor of electricity and heat and when exposed to air, it does not tarnish. Because of these properties, gold can be used in the production of printed circuit boards and electrical connectors. Gold is also widely used in electronics, electric wiring, and more. It is very effective as a component because it is malleable and resistant to corrosion.

In addition, gold is used to make dental fillings, decorative items, and coins. The unit karat is used to measure the gold amount is alloys. One karat equals one part in 24; thus, an 18-karat gold earring contains 6 parts alloy and 18 parts gold.

Gold is most frequently found in the oxidation states +1 (aurous compounds or gold (I)) and +3 (auric compounds or gold (III)). The metal is also extremely dense – one cubic meter weighs almost 20 kg. The density of lead is much lower – one cubic meter weighs around 11 kg.

Gold has only one isotope that is found in nature. It has 36 known radioactive isotopes, which are synthetic. Gold is extremely valuable and has sustained its value over time, notwithstanding highs and lows throughout the course of history. This is why the gold standard was created.

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