Until 1220 when Alchemist Albertus Magnus discovered arsenic, mankind knew only ten elementscarbon, sulphur, gold, silver, copper, iron, lead, tin, antimony and mercury. In the next 500 years alchemists discovered only bismuth, zinc and phosphorus. Then scientific chemistry began By 1900, before which time perspicacious Dmitri Ivanovich Mendeleyeff figured that there must be 92 elements on earth, no more, no less, chemists had isolated 83. Last discovery of a tangible element, which could be handled and weighed, occurred in 1926 when Professor B. Smith Hopkins of the University of Illinois found...
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