S01 The periodic table of the elements.
topic in the S-series we will use a combination of illustration S1 (which
gives the grid structure of the table plus the symbol and atomic number
of each element) together with an overlay illustration which is designed
to highlight a particular point. (Illustration S1 is provided with two
small crosses at the bottom left and top-right, to facilitate correct
positioning of the overlays on the projector.)
|The periodic table of the elements. The basis
of the modern periodic table of the elements was laid down by the Russian chemist Dmitri
Ivanovitch Mendeleev (1834-1907). Mendeleev started his studies at the Central Pedagogic
St.-Petersburg, where he became a private tutor in 1857. Subsequently he worked in Heidelberg (1859- 1861) and the Caucasus. In 1867 he became Professor of Chemistry at
St.-Petersburg and in 1869 he proposed his periodic table of the elements.
Although other authors had also published their own tables, it was Mendeleev's which survived as the basis of the version that we use today. It was a result of Mendeleev's brilliant insight that his table was incomplete indicating that a number of important
elements still remained to be discovered. He left blank spaces for these but was nevertheless able to predict their properties. When at a later date scandium, gallium, germanium and other elements were discovered, these filled in the gaps in his table and provided further confirmation for his theory.
Mendeleev's table was based on ordering the elements according to their increasing atomic weight. This system, however, showed some inconsistencies and was later refined further by Henry Moseley (1887-1915) who ordered the elements according to their increasing atomic number. This gave the periodic table that we use today.