The Father of the Periodic Table: Dimitri Mendeleev
At the age of 32, St. He became a professor of chemistry at St. Petersburg University. To investigate regularities, he listed the elements according to their properties. Thus he obtained the periodic table, which is the silent computer of the chemists. Based on this ruler, he predicted that some elements that were not yet known would be found at that time and some of their properties. The importance of the periodic table was realized a few years later, when some of the elements he had reported on were found, and Mendeleev was recognized as a great scholar.
Mendeleev, the youngest of seventeen siblings, was born in Tobolska, Siberia (1834). His father was a high school principal and his grandfather was the publisher of Siberia's first newspaper. Dimitri did his first education while in exile. After his father's death, his mother went to St.Petersburg for a better education. Petersburg. Dimitri Mendeleev, St. He introduced himself at the University of Petesburg. He made his thesis on the subject of "the combination of alcohol and water" (1856). Dimitri Mendeleev, who met and worked with Bunsen and many European scientists in France and Germany, attended the Karlsruhe (Kalzrue) conference in Germany in 1858. At this conference, there had been fierce debates on the "Avogadro's hypothesis".
He then toured the oil fields in Pennsylvania to see the first oil wells. Upon his return to Russia, he developed a new commercial distillation method. 32 years old St. He became a professor at the chair of inorganic chemistry of St. Petersburg University. The periodic table, which he derived from the regularity in the physical and chemical properties of the elements, was his greatest work. During this arrangement he predicted the existence and properties of some elements that could not be found until then (1869).
The discovery of the elements that he foretold within a few years made Mendeleev a famous chemist around the world in a short time. The periodic table is a striking product of Mendeleev's excellent interpretation and productive intelligence. Mendeleev's other works, consisting of 25 major books, are also quite interesting. His organizing the information on Isomorphism enabled the development of geochemistry. In addition, finding the critical boiling point and developing the hydrate theory of solutions caused him to be known as a great physical chemist.
Mendeleev was a member of some 70 academia and scientific societies. In his own words, his first service was scientific research and the second was teaching. St. He taught at many schools in St. Petersburg.
He died of pneumonia in 1907. When Mendeleev first printed the periodic table, there were 63 elements known. One year after his death, the number of known elements had increased to 86. Such a rapid increase was achieved thanks to the periodic table of the elements, which is the most important generalization of chemistry. Although Mendeleev had not discovered any new elements, due to his service to the scientific world, the element with atomic number 101, which was synthesized by American physicists under the direction of G.T. Seaborg in 1955, was named "mendelevium" in honor of Dimitri Mendeleev.
Generally, German scientist Julius Lothar Meyer and Russian scientist Dimitri Mendeleev are considered to be the father of the periodic table. Both produced remarkably similar results, unaware of the other. Dimitri Mendeleev has seen that certain properties are repeated when the atoms are ordered according to their increasing atomic weight. Later, he prepared a periodic system containing seventeen elements in the first two periods and seventeen elements in the next three periods by ordering the elements one after the other according to their repeating properties. In the periodic system prepared by Dimitri Mendeleev, he left some places blank, thinking that there are yet undiscovered elements. The elements of scandium, gallium, germanium, which were found later, settled in the spaces in the table. In 1895 Lord Rayleigh reported that he discovered a chemically inert new gas (argon). This element could not fit anywhere known in the periodic table.
In 1898, William Ramsay suggested that this element could be placed somewhere between chlorine and potassium. Helium was also considered a member of the same group. This group was called the zero group because of the valence of the elements of this group. Although Dimitri Mendeleev's periodic table shows the periodic properties of the elements, it does not give any information about why the properties are repeated.
In 1911, Ernest Rutherford showed that atomic nuclei could be determined by the scattering experiment of alpha particles. Another thing Rutherford showed was that the charge of a nucleus is proportional to its atomic weight. Again in 1911, A. Van den Broek showed in a series of studies that the atomic weights of the elements are approximately equal to the charge on the atom. This charge was later identified as atomic number and used to place elements in the periodic table.
In 1913, Henry Moseley measured the wavelengths of the X-ray spectral lines of a group of elements, showing that the atomic number and the X-ray wavelengths of the elements were related. This work demonstrated the error in choosing atomic weights as the basis, as did Mendeleev, Mayer and others. However, the answer to the question of why periodic properties are observed begins with Niels Bohr's study of the electronic structure in elements. The last major change in the periodic table emerged in the mid-20th century with the work of Glenn Seaborg. His research, which started with the discovery of plutonium in 1940, continued with the discovery of all trans-uranium elements from 94 to 102. He placed the actinides series under the lanthanide series in the periodic table. In 1951 Seaborg won the Nobel prize in chemistry for these studies. Element 106 was named seaborium (Sg).
The periodic table is a product of Mendeleev's interpretation and exploration. Mendeleev's work consists of 25 major books. His organization of information about isomorphism enabled the development of geochemistry. In addition, finding the critical boiling point and developing the hydrate theory of solutions caused him to be known as a great physical chemist. Mendeleev was a member of some 70 academia and scientific societies. In his own words, his first service was scientific research and the second was teaching.