Formulator of the Periodic Table

Dmitri Mendeleev

What is a mark of a great scientist? Good scientists discover new information and make sense of it, linking it to other data. They may go further by giving an explanation of this linked data which, maybe not immediately, other scientists accept as a correct explanation. However the outstanding scientist goes further in predicting consequences of his ideas which can be tested. This boldness identifies the great scientist if the predictions are later found to be accurate. One such person was Russian chemist Dmitri Mendeleev. Incidentally, although he is often regarded as the father of the Periodic Table, Mendeleev himself called his table, or matrix, the Periodic System.

Formulator of the Periodic Table

A commemorative stamp collector’s miniature sheet showing some of Mendeleev’s original notes. Horizontal lines like Cr, Mo and W (in the third row down) correspond to today's groups. Note the date, 17 February 1869.

Other people, like Londoner John Newlands, Frenchman Alexandre Bйguyer de Chancourtois and German Julius Lothar Meyer made important contributions to the first Periodic Table but the main credit goes to Mendeleev. All of them were helped by the publication in 1860 of more accurate atomic weights, as relative atomic masses were then called. There were two main problems about establishing a pattern for the elements. First only 60 elements had been discovered (we now know of over 100) and second some of the information about the 60 was wrong. It was if Mendeleev was doing a jigsaw with one third of the pieces missing, and other pieces bent!

Mendeleev had written the properties of elements on pieces of card and tradition has it that after organising the cards while playing patience he suddenly realised that by arranging the element cards in order of increasing atomic weight that certain types of element regularly occurred. For example a reactive non-metal was directly followed by a very reactive light metal, then a less reactive light metal. The image of a stamp collectors’ miniature sheet shows a stamp commemorating the hundredth anniversary of the Periodic Table superimposed on some of Mendeleev’s original jottings.

Shortly after, his ideas were presented to the Russian Physico-chemical Society. They were read by Professor Menschutkin because Mendeleev was ill. His ideas were then published in the main German chemistry periodical of the time, Zeitschrift fϋr Chemie.