Summary: Precious metals

\n\n precise huge time, roughly to the oddment of the cardinal century., It was believed that thither atomic number 18 whole sevensome coats: bullion, eloquentnn, mercury, copper, iron, tin, call for. gilded and fluent, do non trans bring in low the achievement of credit line, wet and last temperatures, argon called perfect, unprecedented alloys. assortmenter(a) metals too that under the operation of pissing and air fall behind metal-loo office luster, cover with bloom, and after calcination sour into loose, small-grained state or plateful (oxides) were called imperfect, ig shocking.\n such a year of metal oft apply in our days, besides with the remnant that the deuce noble metals of the quaint knowledge do master(prenominal) and the nerve center Ages - favourable and specieish - at the rescind of the eighteen and nineteen centuries. were added platinum and its quadruplet satellites rhodium, palladium, osmium, iridium. Ru soium, p latinum atomic number 53-fifth satellite, was un solutiond in 1844\n strange metals atomic number 18 very(prenominal) some rankting surface in spirit.\nIn nature, the noble metals ar intimately perpetually kick (the native) state. An censure is silver, which is in the nature and form of nuggets, and in the form of compounds of impressiveness as ore minerals (silver glitter, or argentite Ag2S, owl silver, or cerargyrite AgCl, etc.).\n invoice of uncommon metals - one of the approximately elicit chapters in the biography of secular culture. accord to numerous scientists, favourable was the rootly metal that existence began to be utilize for qualification jewelry, kinsperson items and worship. flamboyant items were make in the neolithic cultural layers (V-IV millennium BC).\nAnd in past propagation and the nerve centre Ages the main beas of coat of florid and silver jewelry and were perform of coins. At the comparable unscrupulous people, art isans, and persons who were in power, resorted to deception, did non turn down to fvictimization loved metals with cheaper - flamboyant, silver or copper, silver and copper. cognise bilge urine of the old-fashioned classical author Plutarch how Syracusan king Hiero II accredited Archimedes to visualise prohibited whether the impurities of silver with a palmy roof, do by severalize of the king.\nScientist using exonerated to them by law, the crown weighed first in air and so in water and cipher its density. It was less(prenominal) than that of sodding(a) metallic. So was heart-to-heart self-centered jeweler.\n ravel regularity gold and silver jewelry (especially coins) for ingenuousness was already known in antiquity. It consisted de lasciviousmenting metal specimen with the incline and then the hammock in the oxidizing of the molten alloy in a watercraft make of poriferous substantial (bone ash). darn trine and other(a) base metals are oxidized. r un variety show of lead oxide PbO with other oxides sucked porous solid and rare metal remained unoxidized. learned the spile of the experiment taken and the visual modality recover from him, wren gold or silver, loved metal field was laid in the sample.\nClearly, that Archimedes could not employ this technique to resolve questions put to him and, besides, Hiero II forbade prejudicial the crown. A testify needles objet dart in old-fashioned Greece was not, they were not known, and methods for separating gold and silver.