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Dmitri Mendeleev
1834–1907 · Chemist & Inventor
A Russian chemist who developed an influential early periodic table, recognised periodic patterns and predicted properties of elements not yet discovered.
“The elements which are the most widely diffused have small atomic weights.”
Why is this scientist famous?
Developed an influential periodic table and periodic law, leaving gaps for undiscovered elements and predicting several of their properties.
Mendeleev's 1869 periodic table was part of a wider nineteenth-century effort to organise the elements, with scientists including John Newlands and Lothar Meyer making important contributions. Mendeleev's version became especially influential because he left gaps for undiscovered elements and made detailed predictions that were later confirmed.
Dmitri's story
Early Life
Born in 1834 in Tobolsk, Siberia, Mendeleev was the youngest in a large family; historical sources disagree on the exact number of children. After his father's death and the loss of the family glassworks, his mother travelled a great distance with Dmitri to help him continue his education in St Petersburg.
The Periodic Table
By the 1860s several chemists were trying to find patterns among the known elements. In 1869 Mendeleev published a table arranging the elements mainly by atomic weight and chemical properties and formulated the periodic law. His crucial step was to leave gaps where the pattern suggested elements were missing and to predict some of their properties.
Predictions Confirmed
Mendeleev predicted the properties of gallium, germanium, and scandium — elements no one had discovered yet. When they were found in the 1870s and 1880s, their properties matched his predictions almost exactly. This convinced the scientific world that his table was correct.
Beyond Chemistry
Mendeleev worked on many subjects beyond the periodic law, including solutions, gases, petroleum and industrial chemistry. He advised Russian industry and government, carried out research connected with smokeless powder, and in 1893 became director of Russia's Bureau of Weights and Measures, where he supported accurate measurement and wider use of the metric system.
What did they discover?
The Periodic Table of Elements
Published one of the most influential early periodic tables in 1869, building on a wider effort by nineteenth-century chemists to organise the elements.
Predicting Undiscovered Elements
Predicted properties of elements later identified as gallium, scandium and germanium; their discoveries strongly supported his periodic system.
The Concept of Periodicity
Formulated the periodic law, recognising repeating patterns in chemical properties when elements were arranged mainly by atomic weight.
Amazing facts
A famous later story says Mendeleev saw the periodic table in a dream, but historians treat this as an anecdote rather than a documented account of how he developed it.
He was the youngest of 14 or 17 children — sources disagree on the exact number.
After family hardship in Siberia, his mother travelled a great distance with him so that he could continue his education in St Petersburg.
Element 101, Mendelevium (Md), is named after him.
He helped introduce the metric system to Russia and worked on the Russian oil industry.
In 1893 he became director of Russia's Bureau of Weights and Measures and promoted accurate measurement and the metric system.
Timeline
Born in Tobolsk, Siberia, Russian Empire on February 8
Entered the Main Pedagogical Institute in St. Petersburg to study chemistry
Studied in Heidelberg, Germany under prominent chemists
Completed his doctoral dissertation on solutions
Appointed to the chair of chemistry at the University of St Petersburg
Presented his Periodic Table of Elements to the Russian Chemical Society
Published an improved periodic table with predictions for undiscovered elements
Gallium discovered, matching his predictions — his table gained credibility
Scandium discovered, closely matching another of his predictions
Germanium discovered, further confirming his predictions
Elected a Foreign Member of the Royal Society
Became director of Russia's Bureau of Weights and Measures
Died in St. Petersburg on February 2, age 72
Awards & honours
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