Dmitry Ivanovich Mendeleev

👶 Dmitri Ivanovich Mendeleev was born in 1834 in Tobolsk into the family of a gymnasium director. He was the youngest of seventeen children and lost his father early, as his father went blind and retired from service even before Dmitri's birth. The upbringing of the children and the management of the family's glass factory fell to his mother, Maria Dmitrievna, an energetic and enterprising woman who recognized her youngest son's exceptional aptitude for the sciences. After a fire destroyed the factory and his father died, the family moved first to Moscow and then to Saint Petersburg, where Dmitri enrolled at the Main Pedagogical Institute. 🎓 After graduating from the institute, Mendeleev engaged in teaching and research, undertook a fellowship in Germany, where he worked in Robert Bunsen's laboratory and studied physical chemistry. Upon returning to Russia, he defended his doctoral dissertation and became a professor at Saint Petersburg University. During this period, the scientist actively studied the chemistry of solutions, investigated the properties of gases, and worked on his textbook "Principles of Chemistry," which later became a classic work of inorganic chemistry. 🧪 Mendeleev's principal scientific achievement was his 1869 discovery of the periodic law of chemical elements, on the basis of which he created the periodic table. By arranging elements according to increasing atomic mass, the scientist discovered a regular recurrence of chemical properties and boldly left empty spaces in the table for elements not yet discovered, accurately predicting their properties. The subsequent discoveries of gallium, scandium, and germanium brilliantly confirmed the accuracy of his theoretical calculations and brought Mendeleev worldwide renown. 🌍 Beyond the periodic law, Mendeleev made substantial contributions to numerous fields of science and practice: he studied the thermal expansion of gases, worked on questions of metrology, engaged with Russia's oil industry and agriculture, and participated in establishing the first Russian standard of weights and measures. He was elected a member of numerous foreign academies of sciences, though he never became a full academician of the Saint Petersburg Academy of Sciences. The scientist died in 1907 in Saint Petersburg from pneumonia, leaving behind an enormous scientific legacy that remains relevant to this day.