More than 150 years ago, a great Russian scientist shared with the world a discovery that forever changed the understanding of chemistry. Mendeleev's periodic table: how and when it was discovered, how it was improved and how it influenced the future of the world of science.
History of Mendeleev's Periodic Table
The periodic table of chemical elements, or as we used to call it, the periodic table is a graphical expression of the periodic law, discovered by scientists in 1869. The law itself was formulated by Dmitry Ivanovich Mendeleev in the following form: "The properties of the elements, and therefore the properties of the simple and complex bodies they form, are in a periodic dependence on their atomic weight."
Attempts to classify chemical elements based on their properties were made by scientists from all over the world long before Mendeleev. However, their works could not claim to be a fundamental description of everything due to the lack of theoretical information about atomic masses and the basic properties of chemical elements.
The original form of the table, proposed by Mendeleev in 1869, was significantly different from the version that we are used to seeing at the present time. The elements in this table were arranged in nineteen horizontal rows and six vertical columns. By the way, in total, according to some estimates, several hundred different ways of graphical expression of the periodic law were proposed.
The greatness of Mendeleev's work lay in the discovery of the periodicity of the properties of chemical elements depending on their atomic mass. That is, the properties of a number of elements located in the table at a certain distance from each other are largely similar and are determined precisely by the position of the element in the table.
After the discovery and publication, the table was modified several times, including by Mendeleev himself. In many ways, the improvement of the table is due to the development of physics at the beginning of the 20th century. The discovery of the divisibility of the atom explained the causes of periodicity and made it possible to replenish the table with a number of new chemical elements.
Interesting facts
- Each of us is familiar with the myth that the idea of the structure of the periodic table came to Mendeleev in a dream. Here is the commentary of the scientist himself about this: “I’ve been thinking about it for maybe twenty years, and you think: I sat and suddenly ... it’s ready.”
- It is widely believed that Mendeleev devoted his entire life to the knowledge and development of chemistry. However, according to biographers of Dmitry Ivanovich, only about 10% of his works are devoted to chemistry. Indeed, the scientist was distinguished by extensive knowledge in many fields of science. For example, Mendeleev is one of the creators of the world's first Arctic icebreaker and the author of more than forty works on Arctic navigation.
- The names of many chemical elements in the periodic table are based on Latin words that describe their special properties. In addition, a significant part of the elements are named after great scientists, heroes of ancient Greek mythology and geographical objects.
- At the time of publication, there were several empty cells in the periodic table. The elements that should have been in them were simply not yet open. However, relying on the phenomenon of the periodicity of chemical properties, Mendeleev gave an absolutely accurate description of the elements, the discovery of which took place only a few years later.
- The table continues to be updated with new elements at the present time. So, in the 21st century, four new chemical elements were discovered, the last of which was synthesized quite recently - in 2010. The work to create new elements in nuclear physics centers around the world has been called the "great race".
The discovery of the periodic law by Mendeleev largely determined the development of future science. Such a contribution can be made by each of us: it requires only hard work and a love of knowledge!
