by whom was this table first developed?
Dmitri Mendeleev
Periodic table
Russian chemist Dmitri Mendeleev published the first recognizable periodic table in 1869, developed mainly to illustrate periodic trends of the then-known elements.
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
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Periodic table [SEP] Introduction
Numerous synthetic radioisotopes of naturally occurring elements have also been produced in laboratories. The organization of the periodic table can be used to derive relationships between the various element properties, and also to predict chemical properties and behaviours of undiscovered or newly synthesized elements. Russian chemist Dmitri Mendeleev published the first recognizable periodic table in 1869, developed mainly to illustrate periodic trends of the then-known elements. He also predicted some properties of unidentified elements that were expected to fill gaps within the table. Most of his forecasts soon proved to be correct, culminating with the discovery of gallium and germanium in 1875 and 1886 respectively, which corroborated his predictions.