Student Education Repository (மாணவர்கள் கல்விக் களஞ்சியம்): Today (February 2, 1907) is Dmitry Mendeleev's Memorial Day, the creation of the first periodic table based on the atomic weights of the elements.

Tuesday, February 2, 2021

Today (February 2, 1907) is Dmitry Mendeleev's Memorial Day, the creation of the first periodic table based on the atomic weights of the elements.

Today (February 2, 1907) is Dmitry Mendeleev's Memorial Day, the creation of the first periodic table based on the atomic weights of the elements.

Dimitri Mendeleev was born on February 8, 1834, in Tobolsk, Siberia, Russia, the 17th last son of Ivan Pavlovich Mendeleev and Maria Dimitrievna Mendeleev. His father died when he was 13 years old. Mother's factory was destroyed by fire. Mendeleev's family moved to St. Petersburg in 1849. There he joined the Dmitry Teacher Training College in 1850 and graduated. Mendeleev contracted tuberculosis in 1855 and had to move to Crimea in the Black Sea. After a full recovery, he returned to St. Petersburg in 1857. Between 1859 and 1861 he was involved in chemical research in Heidelberg, Germany. In 1861 he wrote and published a book on spectroscopy. The book was awarded the Demidov Prize by the Petersburg Academy of Sciences. This earned him great fame.

In 1862 Mendeleev became a professor of chemistry at St. Petersburg Government Technical College. In 1863 he became a professor at St. Petersburg State University. He received his doctorate in 1865 for his study of the combination of alcohol with water. In 1863 56 elements were known. At that time the elements were discovered at a rate of about one per year. Other scientists previously knew the definitions of molecules and the periodic properties of elements. In 1864, John Newlands described the hexadecimal law, considering the similarity that occurs when comparing eight elements into atomic weights. It was published in 1865 as Newland's Eighth Law. Based on this new elements such as germanium were identified. Until 1887 his discoveries were criticized without being approved by the Chemical Society.

In 1864 Lothar Meyer proposed a concept of the periodic properties of elements based on the parallel properties of 28 elements. But there are no predictions about new elements in it. Mendeleev later became a teacher and wrote a two-volume book, The Philosophy of Chemistry (1868-1870), for students. He made it into a textbook for his curriculum. This book was written when he made his most important discovery. When he tried to classify elements based on chemical properties, the concept of the periodic table emerged, which predicted periodic properties. When he got a lot of information about the atom, he prepared an elementary table for himself. He said he had dreamed of that table with all the elements.

Happy Birthday Dmitri Ivanovich Mendeleev - GIF on Imgur

"In my dream, I saw a table where all the elements were in their proper place. I immediately got up and wrote it down on a piece of paper. Unaware of previous work on periodic table preparation in the 1860s, he prepared the table. The longitudinal periodic table was formed when other elements were added in this manner. On March 6, 1869, Mendeleev submitted his table to the Russian Institute of Chemistry entitled "The properties of elements depend on their atomic weights". In it, he described both atomic weight and covalence as elements that explain the properties of elements. He completed the table by anticipating the properties of many undiscovered elements in the table at the time. A few months after Mendeleev unveiled the table, Julius Meyer of Germany announced a similar table.

No, this is a periodic table - GIF on Imgur

If the elements are arranged in ascending order according to their atomic weights, their properties will be revealed to be periodic. Elements with similar chemical properties may have the same atomic weights (eg platinum, iridium, osmium) or their atomic weights may be in sequence (eg potassium, rubidium, cesium). The parallelism of the elements in a series in the order of atomic weight varies according to their atomic weights. Similarly, to a significant extent, they are similar to their unique chemical properties. It is found in lithium, beryllium, boron, carbon, nitrogen, oxygen and fluorine. Elements with low atomic weights are highly permeable. Atomic weight determines the properties of elements, just as molecules determine the nature of a substance. We should expect the discovery of many unknown elements (example: two elements: similar to aluminium and silicon with their atomic weights ranging from 60 to 75).

The atomic weights of the elements can sometimes be corrected by the knowledge of the elements next to them. The atomic weight of tellurium should be between 123 and 126, not 128. (The atomic mass of tellurium is 127.6, and Mendeleev in a series assumed that the atomic weight should increase steadily). Some characteristic properties of elements can be predicted by their atomic masses. Dmitry Mendeleev published a periodic table of all known elements in a Russian language scientific journal. He predicted many new elements that could complete the table. A few months later, Meyer published a similar table in the German Journal of Linguistics. Some consider Meyer and Mendeleev to be co-creators of the periodic table. According to Mendeleev's table, based on the properties of germanium, gallium and scandium, he accurately predicted the properties of the undiscovered elements eco styling, aluminium and ecoperone.

He used the nicknames Eka, tie, and tri (one, two, three in Sanskrit) for naming the eight elements that appeared in his calculation. Mendeleev raised questions about some of the atomic weights of the elements accepted in his time. (Atomic weights could only be measured with low accuracy at the time). He pointed out that they did not correspond to the periodic rule recommended by his timeline. He noted that tellurium has a higher atomic weight than iodine. And he put them in the right order. The atomic weights accepted at the time were predicted to be wrong. He was confused about where to place the known Langhans. And predicted that atomic mass actinides would be in another order in the same table. Some rejected Mendeleev's predictions that there were more elements. But in 1875 and 1886 he proved that Ga (gallium) and Ge (germanium) matched the properties specified in the blanks, respectively.

By giving Sanskrit names to elements on the list of "undiscovered elements" according to his policy, Mendeleev expressed his admiration and gratitude to the Sanskrit grammarians of ancient India. His work was a way of thanking grammar scholars for inventing two-dimensional forms of basic sounds, the most advanced principles of language. Mendeleev was a friend of the Sanskrit Böhtlingk. At the time, Poutling was preparing the second edition of his book, Pāṇini. Mendeleev wanted to honour Bowling by incorporating these into the nomenclature for the elements.

Dynamic periodic table of the elements in Excel. Clever! | Periodic table of the elements, Periodic table, Elementary chemistry

When elements were at odds by atomic weight, Mendeleev gave priority to homogeneity. (Example: In terms of atomic weight, although similar to the elements nitrogen and phosphorus, the element magnesium is placed in the beryllium family based on its properties). Their periodic characteristic discoveries at both levels were later explained by the theory of internal structure. The original draft, invented and developed by Mendeleev, will be published many years later as a book entitled "Temporary Structure of Elements". Dmitry Mendeleev is referred to as the father of the column table. He refers to the instrumentation or table of information in his columns and columns as the periodic system. It is a remarkable achievement that Mendeleev defined the properties of elements not discovered in his time. Dmitry Mendeleev, who developed the first periodic table based on the atomic weights of elements, passed away on February 2, 1907, at the age of 72 in St. Petersburg.

Source By: Wikipedia.

Information: Ramesh, Assistant Professor of Physics, Nehru Memorial College, Puthanampatti, Trichy.