24 artificial elements are in the periodic table.
24 artificial elements are in the periodic table.
how many artificial elements are in the periodic table?
24
russian chemist dmitri mendeleev arranged the elements by atomic mass, corresponding to relative molar mass. it is sometimes said that he played "chemical solitaire" on long train journeys, using cards with various facts about the known elements. mendeleev used the trends he saw to suggest that atomic weights of some elements were incorrect and accordingly changed their placing: for instance, he figured there was no place for a trivalent uranium with the mass of 120 in his work, and he doubled both the atomic weight and valency of uranium, suggesting it was a hexavalent element with the atomic weight of 240. mendeleev also figured some spots in his ordering had no element to match, and he left gaps on account of future discoveries of these elements, using the elements before and after those missing ones to predict their properties. in 1869, he finalized his first work and had it published. mendeleev also sent it to a number of well-known chemists, including meyer; this preceded meyer's first comprehensive periodic table which he published a few months later, acknowledging mendeleev's priority. mendeleev continued to improve his ordering; in 1870, it gained a tabular shape, and in 1871, it was titled "periodic table". some changes also occurred with new revisions, with some elements changing positions.
history of the periodic table
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section::::isotopes for elements 15-29.









































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section::::isotopes for elements 30-44.









































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section::::isotopes for elements 45-59.









































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section::::isotopes for elements 60-74.









































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section::::isotopes for elements 75-89.









































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table of nuclides (segmented, narrow)