Quantum Mechanics and Periodic Table

Theoretical justification of the Madelung rule was given by Wong using the Fermi-Thomas statistical model as an approximation of the quantum atom. In 1871, Dimitri Mendeleev presented a new form of his periodic table where similar elements were arranged in the same column, resembling the representative group of modern periodic table for the first rows of this table. Both Mendeleev and Julius Lothar Meyer are regarded as the authors of the periodic table, although the highest credit is given to Mendeleev, owing to the prediction capacity of his model. The atomic radius directly influences another very important periodic property: the electronegativity. The electronegativity is the tendency of a neutral atom or ion to attract electrons or charge density which depends inversely on its atomic radius. Electronegativity is a very important property that must always be recalled by the students in order to explain a series of physical and chemical properties.