Dmitri Mendeleev believed he was a great scientist and indeed he was. He was not actually recognized as such until his periodic table achieved worldwide diffusion and began to appear in textbooks of general chemistry and in other major publications. When Mendeleev died in February 1907, the periodic table was established well enough to stand on its own and perpetuate his name for upcoming generations of chemists.
The man died, but the myth was born.
Mendeleev as a legendary figure grew with time, aided by his own well-organized promotion of his discovery. Well-versed in foreign languages and with a sort of overwhelming desire to escape his tsar-dominated homeland, he traveled the length and breadth of Europe, attending many conferences in England, Germany, Italy, and central Europe, his only luggage seemingly his periodic table.
Mendeleev had succeeded in creating a new tool that chemists could use as a springboard to new and fascinating discoveries in the fields of theoretical, mineral, and general chemistry. But every coin has two faces, even the periodic table. On the one hand, it lighted the path to the discovery of still missing elements; on the other, it led some unfortunate individuals to fall into the fatal error of announcing the discovery of false or spurious supposed new elements. Even Mendeleev, who considered himself the Newton of the chemical sciences, fell into this trap, announcing the discovery of imaginary elements that presently we know to have been mere self-deception or illusion.
It probably is not well-known that Mendeleev had predicted the existence of a large number of elements, actually more than ten. Their discoveries were sometimes the result of lucky guesses (like the famous cases of gallium, germanium, and scandium), and at other times they were erroneous. Historiography has kindly passed over the latter, forgetting about the long line of imaginary elements that Mendeleev had proposed, among which were two with atomic weights lower than that of hydrogen, newtonium (atomic weight = 0.17) and coronium (Atomic weight = 0.4). He also proposed the existence of six new elements between hydrogen and lithium, whose existence could not but be false.
Mendeleev represented a sort of tormented genius who believed in the universality of his creature and dreaded the possibility that it could be eclipsed by other discoveries. He did not live long enough to see the seed that he had planted become a mighty tree. He fought equally, with fierce indignation, the priority claims of others as well as the advent of new discoveries that appeared to menace his discovery.
In the end, his table was enduring enough to accommodate atomic number, isotopes, radioisotopes, the noble gases, the rare earth elements, the actinides, and the quantum mechanics that endowed it with a theoretical framework, allowing it to appear fresh and modern even after a scientific journey of 145 years.
Image: Nursery of new stars by NASA, Hui Yang University of Illinois. Public domain via Wikimedia Commons.