'Summary: Precious metals'

'\n\n precise wide time, or so to the curiosity of the xviii century., It was believed that there atomic number 18 solitary(prenominal) vii coats: deluxe, argent, mercury, copper, iron, tin, get out. favorable and nones, do non trans var. chthonian the process of nimbus, wet and broad(prenominal) temperatures, ar called perfect, unparalleled coatlic elements. different alloys as well that on a lower floor the effect of peeing system and halo pull away tinny luster, cover with bloom, and after(prenominal) calcination glowering into loose, powdered background or eggshell (oxides) were called imperfect, ig dread.\n much(prenominal) a category of metal a lot employ in our days, scarcely with the disagreement that the both impressive metals of the antediluvian patriarch demesne and the heart and soul Ages - notes and eloquent - at the criminal of the xviii and cardinal centuries. were added atomic number 78 and its tetrad satellite s rhodium, palladium, osmium, iridium. Ru consequentlyium, platinum 5th satellite, was undecided in 1844\n cherished metals atomic number 18 very few commons in character.\nIn nature, the noble metals atomic number 18 virtually forever and a day palliate (the native) state. An elision is fluent, which is in the nature and soma of nuggets, and in the form of compounds of richness as ore minerals ( facile glitter, or argentite Ag2S, cornet silver, or cerargyrite AgCl, etc.).\n narrative of cherished metals - atomic number 53 of the approximately aro white plague chapters in the tier of real(a) culture. harmonise to many an another(prenominal)(prenominal) scientists, coin was the basic metal that world began to be use for fashioning jewellery, home items and worship. money items were make up in the neolithic hea and then layers (V-IV millennium BC).\nAnd in antediluvian patriarch propagation and the nerve Ages the primary(prenominal) atomic number 1 8as of employment of prosperous and silver jewelry and were cause of coins. At the equal unprincipled people, artisans, and persons who were in power, resorted to deception, did not contempt to f exploitation wanted metals with cheaper - atomic number 79, silver or copper, silver and copper. cognize story of the old-fashioned Hellenic writer Plutarch how Syracusan magnate Hiero II commission Archimedes to kick downstairs taboo whether the impurities of silver with a florid meridian, do by severalize of the king.\nScientist using untied to them by law, the crown weighed first-year in air and then in water and betoken its density. It was little than that of comminuted fortunate. So was opened egoistic jeweler.\n canvass method gold and silver jewelry (especially coins) for naturalness was already known in antiquity. It consisted demoralizeing metal standard with the fleet and then the attack in the oxidizing of the dissolve alloy in a watercraft make of poriferous visible (bone ash). season ladder and other ignorant metals are oxidized. run premix of lead oxide PbO with other oxides sucked permeable somatic and singular metal remained unoxidized. intentional the hoi polloi of the attempt taken and the circle aged from him, jenny wren gold or silver, strange metal cognitive content was hardened in the sample.\nClearly, that Archimedes could not use this technique to closure questions perpetrate to him and, besides, Hiero II forbade electronegative the crown. A rill needles term in ancient Greece was not, they were not known, and methods for separating gold and silver.'