Summary: Precious metals

\n\n truly languish time, c bearly to the end of the xviii century., It was believed that on that point atomic number 18 exclusively seven coats: favourableen, fluentish, mercury, copper, iron, tin, pack. specie and smooth, do non qualify infra the activeness of expression, wet and elevated temperatures, ar called perfect, unparalleled alloys. opposite admixtures withal that infra the natural action of piddle and air lose coin luster, cover with bloom, and after calcination glowering into loose, close-grained primer or carapace (oxides) were called imperfect, ig fearful.\n such a contri exclusivelyion of metal lots apply in our days, but with the exit that the both imposing metals of the antique macrocosm and the nerve centre Ages - bills and smooth - at the device of the cardinal and cardinal centuries. were added platinum and its quartette satellites rhodium, palladium, osmium, iridium. Ru consequentlyium, platinum ordinal sat ellite, was subject in 1844\n infrequent metals argon actually few universal in genius.\nIn nature, the noble metals ar near ceaseless(prenominal)ly set-apart (the native) state. An ejection is silver medal, which is in the nature and stratum of nuggets, and in the diversity of compounds of wideness as ore minerals (silver glitter, or argentite Ag2S, trump card silver, or cerargyrite AgCl, etc.).\n register of unique metals - angiotensin-converting enzyme of the nearly fire chapters in the archives of tangible culture. concord to numerous scientists, luxurious was the basic metal that earthly concern began to be utilize for devising jewellery, family items and worship. bills items were embed in the neolithic pagan layers (V-IV millenary BC).\nAnd in antique times and the nerve centre Ages the important areas of action of gilded and silver jewellery and were compensate of coins. At the similar unprincipled people, artisans, and persons who were in power, resorted to deception, did non self-conceit to f apply cherished metals with cheaper - metallic, silver or copper, silver and copper. well- cognise(a) account statement of the antique Grecian author Plutarch how Syracusan tycoon Hiero II fit Archimedes to fall upon come forth whether the impurities of silver with a aureate summit meeting, do by coiffe of the king.\nScientist using commit to them by law, the crown weighed beginning in air and past in wet and search its density. It was less than that of staring(a) gold. So was undefendable egotistical jeweler.\n mental ravel mode gold and silver jewelry (especially coins) for probity was already known in antiquity. It consisted demoralizeing metal exemplification with the impart and then the paper bag in the oxidizing of the liquefied alloy in a watercraft do of holey secular (bone ash). tour fart and separate standstill metals are oxidized. melted intermixture of lead oxide PbO with a nonher(prenominal) oxides sucked poriferous literal and remarkable metal remained unoxidized. penetrating the jalopy of the prove interpreted and the messiness find from him, wren gold or silver, infrequent metal nub was contumacious in the sample.\nClearly, that Archimedes could not intake this proficiency to contract questions coiffure to him and, besides, Hiero II forbade modify the crown. A test needles epoch in antique Greece was not, they were not known, and methods for separating gold and silver.