Mendeleev, The Man Who Changed Chemistry Forever

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. Today we mark 180th birthday of one such true giant in the history of humanity, Russian chemist Dmitri Mendeleev.

Born in Siberia, the last of at least 14 children, Dmitri Mendeleev (1834-1907) revolutionized our understanding of the properties of atoms and created a table that probably adorns every chemistry classroom in the world. After his father went blind and could no longer support the family, Mendeleev’s mother started a glass factory to help make ends meet. But just as Mendeleev was finishing high school, his father died and the glass factory burned down. With most of her other children now out on their own, his mother took her son to St. Petersburg, working tirelessly and successfully to get him into college.

Mendeleev published his periodic table, in which he had organized the 63 elements then known, in 1869. However, he also went further. Since there were gaps in his arrangement of the elements by atomic weight, the Russian chemist predicted the properties that the elements that would occupy those places, once they were discovered.

Indeed, it was not long before the three elements that were to occupy those empty boxes were discovered. These were Germanite – discovered in 1875 – Gallium (1879) and Scandium (1885). And they have the very properties that Mendeleev had predicted based on their position in the periodic table. This demonstrates the validity of his table, since not only had the Russian chemist classified the known elements, but he had also predicted the properties of those still to be discovered.

Mendeleev died in St. Petersburg on 2 February 1907. Forty-eight years later, in 1955, chemical element number 101 was discovered, and was named Mendelevium in his honor.

“No law of nature, however general, has been established all at once; its recognition has always been preceded by many presentiments.” – Dmitri Mendeleev