Little Bits of History

March 6

Posted in History by patriciahysell on March 7, 2017

1869: Dmitri Mendeleev makes a presentation to the Russian Chemical Society. Mendeleev was born in 1834 in the Russian Empire near Siberia. The chemist and inventor was the youngest child in a large family (anywhere from 11 to 17 siblings, depending on sources). His father lost his teaching position when he went blind so his mother went to work reestablishing the family’s abandoned glass factory. By the time Dmitri was 13, the factory had been destroyed by fire, his father had died, and he was enrolled in a local school. In 1849, his mother packed him up and traveled from Siberia to Moscow in order to get Mendeleev a higher education. The University of Moscow did not accept him, and the impoverished family moved to St. Petersburg.

Mendeleev graduated from Main Pedagogical Institute in 1850 but then contracted tuberculosis. He moved to a better climate and continued his studies. When he returned to St. Petersburg, his health was much better. He wrote papers, got married, became a professor, and even got tenure. His love of chemistry led him to make astounding discoveries. In 1863 there were 56 known elements and a new one was discovered about every year. Other scientists had noted the periodicity of the elements and even published on the topic. During this time frame, Mendeleev wrote a definitive textbook for his field, Principles of Chemistry (2 volumes). While writing, he tried to classify elements by their chemical properties. He noticed patterns.

The paper presented on this day noted this pattern. His presentation, The Dependence between the Properties of the Atomic Weights of the Elements, described elements according to both their atomic weight and valence (ability to combine with other elements to form compounds or molecules). He listed eight issues or properties he had found which would create a periodic table where similarities were part of the process. This periodic listing allowed for the prediction of many as yet unknown elements. His work was published at nearly the same time as another scientist and both Mendeleev and Lothar Meyer are listed as co-creators.

Today’s periodic table is usually laid out in 18 columns with a tabular arrangement of the elements listed. They are ordered by their atomic number or number of protons, electron configurations, and chemical properties. This allows some trending to be noted in columns of elements as well as four rectangular blocks where elements have similar properties. Today, there are 118 confirmed elements with Elements 113, 115, 117, and 118 officially confirmed in December 2015. The first 94 elements occur naturally and the remaining 24 can only be obtained by synthesis in a laboratory.

I saw in a dream a table where all elements fell into place as required. Awakening, I immediately wrote it down on a piece of paper, only in one place did a correction later seem necessary.

The analogies between the two systems are striking. Just as Panini found that the phonological patterning of sounds in the language is a function of their articulatory properties, so Mendeleev found that the chemical properties of elements are a function of their atomic weights. Like Panini, Mendeleev arrived at his discovery through a search for the “grammar” of the elements.

No one nor anything can silence me.

I have achieved an inner freedom. – all from Dmitri Mendeleev

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