The specific gravity of gold has been found to vary considerably depending on temperature, how the metal is precipitated, and cold-worked. In 1968, a new International Practical Temperature Scale (IPTS-68) was adopted, which demands that the freezing point of gold be changed to 1064.43C. For many years the temperature assigned to the freezing point of gold has been 1063.0C this has served as a calibration point for the International Temperature Scales (ITS-27 and ITS-48) and the International Practical Temperature Scale (IPTS-48). Gold is available commercially with a purity of 99.999+%. A mixture of one part nitric acid with three of hydrochloric acid is called aqua regia (because it dissolved gold, the King of Metals). Disodium aurothiomalate is administered intramuscularly as a treatment for arthritis. Gold has 18 isotopes 198Au, with a half-life of 2.7 days, is used for treating cancer and other diseases. The most common gold compounds are auric chloride and chlorauric acid, the latter being used in photography for toning the silver image. It is used for coating certain space satellites, as it is a good reflector of infrared and is inert. It is also extensively used for jewelry, decoration, dental work, and for plating. It is used in coinage and is a standard for monetary systems in many countries. It is a good conductor of heat and electricity, and is unaffected by air and most reagents. It is a soft metal and is usually alloyed to give it more strength. It is the most malleable and ductile metal 1 oz. The Purple of Cassius is a delicate test for auric gold. It is metallic, having a yellow color when in a mass, but when finely divided it may be black, ruby, or purple. Of all the elements, gold in its pure state is undoubtedly the most beautiful. It is estimated that all the gold in the world, so far refined, could be placed in a single cube 60 ft. As yet, no method has been found for recovering gold from sea water profitably. Gold occurs in sea water to the extent of 0.1 to 2 mg/ton, depending on the location where the sample is taken. Refining is also frequently done by electrolysis. The metal is recovered from its ores by cyaniding, amalgamating, and smelting processes. production comes from South Dakota and Nevada. About two thirds of the world's gold output comes from South Africa, and about two thirds of the total U.S. It occurs in veins and alluvial deposits, and is often separated from rocks and other minerals by mining and panning operations. Gold is a transition metal and a group 11 element. Gold is a bright, slightly reddish yellow, dense, soft, malleable, and ductile metal. Known and highly valued from earliest times, gold is found in nature as the free metal and in tellurides it is very widely distributed and is almost always associated with quartz or pyrite. Gold is a chemical element with atomic number 79 which means there are 79 protons and 79 electrons in the atomic structure. For example, most noble gases have names ending with -on, while most halogens have names ending with -ine.5, 3, 2, 1, −1, −2, −3 (an amphoteric oxide) The names of some elements indicate their element group.If there is a second letter, it is lowercase. Each element has a symbol, which is one or two letters.The periodic table lists the elements in order of increasing atomic number.Each element is identified by the number of protons in its atoms.There are 118 elements on the periodic table.
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