Jáchymov 227 zentners [11.35 tonnes] were produced), nickel, bismuth and uranium ore were also extracted. There were also other industries: an enormous tobacco factory employed 1,000 women. In addition, there was the manufacture of gloves and corks and of bobbin lace. On 31 March 1873 the town almost entirely burnt down. At the end of the 19th century, Marie Curie discovered, in tons of pitchblende ore containing uraninite from Joachimsthal, the element radium, for which she won the Nobel Prize in Chemistry. Until the First World War this was the foremost source of radium in the world. The first radon spa
Period 7 element of the table's sixth and seventh rows (periods). "Transactinide elements" (also, transactinides, or super-heavy elements) are the chemical elements with atomic numbers greater than those of the actinides, the heaviest of which is lawrencium (103). All transactinides of period 7 have been discovered, up to oganesson (element 118). Transactinide elements are also transuranic elements, that is, have an atomic number greater than that of uranium (92), an actinide. The further distinction of having an atomic number greater than the actinides is significant in several ways: Transactinides are radioactive and have only been obtained synthetically in laboratories. None of these elements