who is credited with deriving the electronegativity values of the periodic table
Electronegativity The term "electronegativity" was introduced by Jöns Jacob Berzelius in 1811,[2] though the concept was known even before that and was studied by many chemists including Avogadro.[2] In spite of its long history, an accurate scale of electronegativity was not developed until 1932, when Linus Pauling proposed an electronegativity scale, which depends on bond energies, as a development of valence bond theory.[3] It has been shown to correlate with a number of other chemical properties. Electronegativity cannot be directly measured and must be calculated from other atomic or molecular properties. Several methods of calculation have been proposed, and although there may be small differences in the numerical values of the electronegativity, all methods show the same periodic trends between elements.
History of the periodic table The Russian chemist Dmitri Mendeleev was the first scientist to make a periodic table similar to the one used today.[citation needed] 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.[21] On March 6, 1869, Mendeleev gave a formal presentation, The Dependence Between the Properties of the Atomic Weights of the Elements, to the Russian Chemical Society. In 1869, the table was published in an obscure Russian journal and then republished in a German journal, Zeitschrift fÃ¼r Chemie.[22][23] In it, Mendeleev stated that: