Dmitri Mendeleev and the Periodic Table

Dmitri Mendeleev and the Periodic Table, linocut by Ele Willoughby, 2021

 

Here’s my Dmitri Mendeleev block print for the Printer Solstice prompt “elements”. I had meant to make his portrait for the 150th anniversary of the periodic table in 2019, but I didn’t get to it. I couldn’t quite figure out how to indicate what he did, in contrast to our modern periodic table. So many people would recognize the shape of the periodic table, from high school, even if they aren’t scientists who use it regularly. But Mendeleev didn’t publish his idea in a form that’s easy to recognize.

First, his table, as published in 1869, is rotated by 90° so it shows groups in rows rather than columns. Second, prior to the discovery of protons and neutrons, he listed and organized elements by atomic weight (now called atomic mass), rather than atomic number (or number of protons). Third, some of his data wasn’t great, so sometimes elements appeared to have the same mass, or were out of order or even were mixtures. He lists Didymium, which is actually a mixture of the elements Praseodymium & Neodymium.

Sometimes you need to think about visual ideas for a long time. Rather than including his notes, or published results as well as a modern periodic table, my idea is to show how much of the modern periodic table he was able to deduce despite limited data. The elements that were unknown or unmeasured are blank- something the viewer can rapidly understand. In several cases he predicted we would find the missing elements in groups (columns). Then, while an impressive amount of the elements known in 1869 are exactly in the right place, there are several which he placed in the wrong groups (due to inaccurate masses). I plan to print those he grouped incorrectly in a different colour. I think this can give an immediate sense of 3 categories: elements he’d figured out, elements he hadn’t quite got right yet, & gaps as of yet unfilled. And if you’ve studied chemistry you can get a sense of what he figured out & why. Even when he placed elements in the wrong group he usual correctly deduced similarities in behaviour found within groups (columns) which we eventually figured out could be explained by structure at an atomic scale.

You can see from Mendeleev's 1869 publication, he got most of the known elements in the right sequence and many in the correct groups. He understood there were connections in properties in adjacent elements and periodicities of properties of elements in the same groups (which he wrote as rows and we now show as columns). He also corrently inferred several as of yet undiscovered elements (see the question marks).

 Mendeleev was born in 1834, in the village of Verkhnie Aremzyani, near Tobolsk in Siberia, the youngest of child of a large family. He was likely the 17th (though 3 older siblings died as infants and there is some dispute among sources). His father was a school principal until he lost his sight and his job. His mother then restarted her family's abandoned glass factory to support the family. His father died and the glass factory was destroyed by fire. Despite economic hardship, 13 year old Mendeleev attended the Gynasium in Tobolsk. In 1849, his mother took him all the way to Moscow to try to get into the university, they were unsuccessful. The now poor Mendeleev family moved to Saint Petersburgh in 1850 so he could instead attend the Main Pedagogical Institute. He graduated, but contracted tuberculosis and went to the Crimean to recover, where he became a science master of the 1st Simferopol Gymnasium. When he was recovered in 1857 he returned to Saint Petersburg. He worked on  capillarity of liquids and the workings of the spectroscope, published the textbook 'Organic Chemistry' and won the Demidov Prize of the Petersburg Academy of Sciences. He married  Feozva Nikitichna Leshcheva (1862), professor at the Saint Petersburg Technological Institute (1864) and Saint Petersburg State University (1865). He got his doctorate on "On the Combinations of Water with Alcohol" in 1865 and got tenure in 1867. He wrote the definitive two-volume chemistry textbook of his day, 'Principles of Chemistry'. By 1871, he had made Saint Petersburgh and international recognized centre of chemical research.

While working on his textbook, he was struck by the periodicity of properties. There had been some earlier, not quite successful attempts to organize elements by properties (of which he was not aware). He claimed to see it in a dream,

"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."
— Mendeleev, as quoted by Inostrantzev

He started with 9 elements, 3 groups of 3 types of properties, then added the other known elements around the core of the table. On 6 March 1869, he presented  ' The Dependence between the Properties of the Atomic Weights of the Elements' to the Russian Chemical Society, using both atomic weight (now called relative atomic mass) and valence. He published his table in a a Russian language journal.

Modern Periodic Table

He correctly noted that if you arrange elements by their atomic mass there show repeating periodic properties. (We now know that atomic number is more important than atomic mass, but they usual would give you the same sequence, especially for lighter elements). He noted similaries in elements of similar atomic weights (that is, adjacent on the table), and similaries in elements in regularly increasing increments (that is, now in the same columns). He realized the elements were ordered by their valencies. He noted that there are more lighter elements. He noted that atomic weight determines properties (though we would now say atomic number). He predicted as-of-yet undiscovered elements at gaps in his table. He inferred that some of the atomic weight data was not quite accurate because the placement in the table did not line up with properties. He noted that knowing the atomic weight could help you predict an element's properties.

He met Anna Ivanova Popova, and divorced his wife in order to marry her, but the divorce was not finalized until a month after his wedding; further the Russian Orthodox Church stipulated 7 years were required between marriages; so, he caused a scandal in 1882. This is likely why he was never admitted to the Russian Academy of Sciences. But he received international acclaim, including receiving the Davy Medal (1882) and Copley Medal (1905) from the Royal Society of London. He resigned from Saint Petersburg University in 1890. He was elected a Foreign Member of the Royal Society (ForMemRS) in 1892. In 1893 he was appointed director of the Bureau of Weights and Measures, for the remainder of his life. He died in at 72, in 1907, from influenza.