who was he?
A Russian chemist and inventor.
Dmitri Mendeleev
Dmitri Ivanovich Mendeleev (often romanized as Mendeleyev or Mendeleef) ( ; , , ; 8 February 18342 February 1907 ) was a Russian chemist and inventor.
what does the column in the periodic table mean The columns, called groups, contain elements with similar chemical behaviours. what is this tabular structure used for? To classify chemical elements which are arranged by atomic number, electron configuration, and recurring chemical properties. The structure of the table shows periodic trends. does this contain only metals? No, it also contains metalloids, nonmetals and noble gases. where are the first one placed in the table? Somewhere between metals and nonmetals what are the different types of the former substance mentioned by you? Boron, silicon, germanium, arsenic, antimony and that of the latter? hydrogen, helium, nitrogen, oxygen,  fluorine, neon by whom was this table first developed? Dmitri Mendeleev
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Dmitri Mendeleev [SEP] Introduction
Dmitri Ivanovich Mendeleev (often romanized as Mendeleyev or Mendeleef) ( ; , , ; 8 February 18342 February 1907 ) was a Russian chemist and inventor. He is best remembered for formulating the Periodic Law and creating a farsighted version of the periodic table of elements. He used the Periodic Law not only to correct the then-accepted properties of some known elements, such as the valence and atomic weight of uranium, but also to predict the properties of eight elements that were yet to be discovered.