Dmitri Ivanovich Mendeleev, a Russian chemist, is known for his publication in 1869 of the first accurate version of the periodic table of elements. The establishment of the Periodic Table of the Elements was a scientific and pedagogic breakthrough and was the first step towards transforming how scientists organized, understood and systematized the elemental building blocks of matter. Mendeleev occupies an important place in the early history of the development and advancement of chemistry. His privileged place in history is due to the outstanding value of his scientific work, which is universally recognized, as well as to his personality. Mendeleev was a Russian genius who built his pedestal in the history of science through patience, sacrifice, hard work, and merit, achieving a degree of superior human perfection. Additionally, he was one of the founders of the Russian Chemical Society in 1869. In 1955, a newly discovered element (number 101) was named mendelevium (Md) in his honor.

This year, the French Academy of Science is celebrating its 350th anniversary, which is the perfect occasion to remember Mendeleev, as he was also a member of the French Academy of Science from 1899.

1 The birth of Mendeleev or a success story of the modern chemist

Mendeleev was born at an exciting time of progress in science, as the development of thermodynamics, electromagnetism, organic chemistry, non-Euclidean geometries, astrophysics, and the theory of evolution were all occurring. In this 19th century, when European capitalism was developed and dominated the society, the development of industry and, implicitly, that of chemical science and technology was necessary. Mendeleev was born on 8 February 1834 in Tobolsk, the historical capital of Siberia, to which his father had been exiled under the Tsarist regime. His father was a Russian intellectual and his mother managed a glass factory. The Mendeleev family had 14 children. From birth, Mendeleev understood that life is a battle and that nothing is free. When his father died in 1849, the family moved to St. Petersburg. His family was imbued with the values of goodness and affirmation through work. In 1849, when he was 15 years old, he enrolled at the Faculty of Petersburg with a focus on physics and mathematics. Due to his strong work ethic and his family's focus on education, Mendeleev studied diligently while at school. To obtain his diploma, at the suggestion of Professor Voskresenski, Mendeleev prepared a brilliant dissertation on crystalline isomorphism for his final examination. Voskresenski (who worked with Liebieg) had a special appreciation for Mendeleev's remarkable talent. He knew how to excite his students by challenging the ideas of the era regarding the nature of chemical combinations. Voskresenski introduced his students to the debate between supporters of the dualistic theory regarding chemical combinations promoted by Berzelius and supporters of the unitary theory of Gerhardt and Laurent. Mendeleev was passionate about the research on specific chemical dates; consequently, after a year of working in Petersburg, he began two dissertation projects on specific volume and the structure of silicon combinations. His prestige thus increased, and Mendeleev became a docent in chemistry and a permanent collaborator on the aspects of applied chemicals at the Journal of Minister Department of Public Works. He graduated from the college in 1855 with honors, distinguished with the gold medal, and earned his degree. During his study at the university, Mendeleev embodied a resilient spirit of learning for the sake of learning without coercion to do so. His professors taught Mendeleev to be open-minded, and he decided to devote his life to the science of chemistry.

After graduation, he worked as a high-school teacher in Odessa and Simferopol. At 23 (in 1857), he lectured at the University of St. Petersburg. Between 1856–1861, he worked in various European laboratories at different positions. When back in his beloved Russia, he was promoted to an associate professor of the Department of Organic Chemistry at the University of St. Petersburg. He wrote the first course in organic chemistry in Russia. This course applies and develops the theory of atomo-molecular organic compounds. It introduced the concept of the “homologous series” before Butlerov developed chemical structure theory. The fact that he expressed himself clearly as well as was passionately engaged in the subject and invested time in it made him an excellent teacher. Mendeleev, who had become a lecturer and teacher with charisma and skill well past age 33, offered Butlerov his place in the organic chemistry department in 1867 when he became the head of the General Department of Technology and began preparing a new course of general chemistry for students.

During his time in Europe, he focused on physical chemistry, which enabled him to explore the elements of internal relationships more solidly. He worked in Paris on the properties of gas and on the Gay-Lussac equation. Due to Voskresenski's insistence, in 1857, he joined Professor Bunsen at the University of Heidelberg. They developed their own laboratory using their financial resources and invested in an extensive and complex characterization of the chemical elements. In Heidelberg, Mendeleev was introduced to certain developments in spectroscopy that Bunsen and Kirchhoff had made. He also encountered Cannizzaro.

The Chemistry teacher never gave up interest in learning and attended many conferences, including one about gasses. In 1860, he participated in the first international chemical congress in Karlsruhe, a congress well known for its debates on the concepts of atoms, molecules, and the equivalent. Innovative methods were discussed at this conference, as well as those of Avogadro and Cannizzaro, who wanted to eliminate existing confusion surrounding atoms and molecules. The definition of the molecule was adopted unanimously at this conference, and afterwards, Mendeleev realized the need for a unitary system of chemical elements.

In 1867, he was invited to attend a meeting in France on world industrial exhibition work opportunities by the Russian Museum and visited France, Germany, Belgium, and many chemical factories and laboratories, which enriched his knowledge. These activities not only increased his understanding of the nature of chemical elements, but also laid the foundation for his discovery of the periodic law of elements.

2 The first periodic table of the elements or Mendeleev primus inter pares

The classification of chemicals was of concern to many scholars since the late 18th century, when Lavoisier, in his Elementary Treatise of Chemistry, presented, in a new order and according to modern discoveries, a table of “substances” regarded in his time as chemical elements. By the mid-19th century, many elements were isolated and characterized. Their masses were accurately calculated, and their chemical properties led to the formation of families, which was an analogy that aroused keen interest. Many chemists worked independently to classify the known elements. In 1817, Döbereiner discovered the existence of similar chemical properties for some elements that appear in groups of three, known as the triads (1929), such as halogens, which include Cl, Br, I; S, Se, and Te, and also Li, K, and Na. He discovered that atomic weights are integer multiples of the mass of hydrogen. The hypothesis of primordial hydrogen was also supported by Meinecke (1818). Several researchers of the period, including Gmelin (1852), Pettenkofer (1850), Dumas (1851), and Chancourtois (1862) attempted to classify the elements based on atomic masses. However, it can be noted that Berzelius disapproved these assumptions. In 1862, a professor of mineralogy, Chancourtois, communicated to the French Academy a series of studies on the “telluric screw”, which classifies the elements according to constant periods; unfortunately, this discovery, very close to that of Mendeleev's, was published in a journal of geology and had little resonance in the scientific community. In 1864, Newlands, a chemical engineer, discovered the “law of octaves”, which shows that some elements with increasing masses have similar chemical properties, such as the alkali metals Li, Na, and K, but this discovery, although accurate, was ignored, ridiculed or treated with mild curiosity and addressed in esoteric articles; however, his work was later justified. In 1869, Meyer discovered the periodicity of the atomic volume of known elements that appear by families. This discovery, unrelated to the work of Mendeleev, leads to similar conclusions. However, among these researchers, Mendeleev was the only one who noted and used in cognitive goals the hidden link between the elements, and he made the greatest contribution. The periodical chart is also organized into rows so that elements with similar valences can all be found in the same column. These elements also showed similarities to several other chemical properties. Additionally, the table is called the periodic table due to periodic repetitions. His version leaves gaps in the table in the right column for undiscovered elements. In its provision of three as an example, it describes properties that the missing elements should have, depending on the other elements above and below them. To Western scientists, this appears to be typical Russian mysticism. However, in 1875, the first matching element was found; in 1879, a second; finally, in 1885, the last of three elements corresponded perfectly to his description. Mendeleev published his first table on 6 March 1869 (which was subsequently revised several times). On 7 January 1871, he presented the most important version of the periodic table, for which he truly deserves all credit to the exclusion of his contemporaries and predecessors, who also contributed. It must be noted that before the introduction of the periodic table, elements were viewed as separate and independent entities. By arranging elements based upon their characteristics, the periodic table enabled scientists to understand the behavior of elements as members of collective sets. Several elements were predicted to exist and were later discovered to fill the original blanks in the periodic table.

Although a series of important events occurred in 1869, such as the creation of the first transcontinental railroad in the US and the inauguration of the Suez Canal (between Europe and Asia), the discovery of Mendeleev's periodic table remained the most important for academia. The periodic table is an important discovery of modern chemistry because it provides a valuable framework to classify and compare the behaviors of chemical compounds. Indeed, the periodic table has served as a guide for the synthesis of new structures and has given us a possibility to understand important scientific advances of our society.

However, Mendeleev's contributions to modern scientific life did not stop with the periodic table. Mendeleev also studied the laws of gas, meteorology, and metrology, the petroleum industry, the oil field, agricultural chemicals, smokeless powder, weights and measures, and so forth.

Mendeleev's personal life was full of “chemical reactions” and “chemical excitements”. Unfortunately, for political reasons, he was forced to resign from the University of St. Petersburg in 1890. He became a scientific advisor for the Russian military service, and three years later, in 1893, he was appointed as the Director of the Bureau of Weights and Measures in St. Petersburg, a post that he occupied until his death. He is credited for improving the standards for vodka and received an awarded for this accomplishment in 1894.

Mendeleev was awarded a membership in the Royal Swedish Academy of Sciences. He was also as corresponding member of the Academy of Paris (1899).

Mendeleev, born in the era of revolutions, lived during an era of capitalism and progress, but departed from the world forever in the era of modernity on 2 February 1907. However, his genius lives on forever.

Mendeleev was not born to seek happiness or take joy in life; instead, he brought joy to others through his work. Mendeleev remained nec pluribus impar.