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The original table was drawn up with no knowledge of the inner structure of atoms: if one orders the elements by atomic weight, and then plots certain other properties against atomic weight, one sees an undulation or periodicity to these properties as a function of atomic mass. These regularities had been recognised by others, but the Russian chemist Dmitry Ivanovich Mendeleev developed the first periodic table, arranging the elements by mass (though he plotted a few elements out of strict mass sequence in to make a better match to the properties of their neighbours in the table - this was later vindicated by the discovery of the electronic structure of the elements in the late 19th and early 20th century. (see also atomic number) |
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The original table was drawn up with no knowledge of the inner structure of atoms: if one orders the elements by atomic weight, and then plots certain other properties against atomic weight, one sees an undulation or periodicity to these properties as a function of atomic mass. The first to recognize these regularities was the German [Johann Wolfgang Doeberreiner]? who noticed a number of triads of similar elements. This was followed by the Englishman [John Alexander Reina Newlands]?, who noticed that the elements of similar type recurred at intervals of eight, which he likened to the octaves of music, though his law of octaves was ridiculed by his contemporaries. Finally the German [Lothar Meyer]? and the Russian chemist Dmitry Ivanovich Mendeleev almost simultaneously developed the first periodic table, arranging the elements by mass (though Mendeleev plotted a few elements out of strict mass sequence in to make a better match to the properties of their neighbours in the table - this was later vindicated by the discovery of the electronic structure of the elements in the late 19th and early 20th century. (see also atomic number) |
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