Every so often in history, there comes a great mind that contributes a great amount of knowledge to the scientific community and the world, so much so that their names become impossible not to mention when speaking of a concept or invention created by them. Names such as Isaac Newton, Galileo Galilei, Albert Einstein, Niels Bohr and Thomas Edison come to mind. 200 years ago, another man was added to the list for his preparation of a periodic table of the elements, which is now a crucial foundation for chemistry, his name was Dmitri Mendeleev.
On February 17th, 1869, on what is dubbed as the birth of the modern periodic table, Mendeleev completed his chart containing all 63 known elements in order of increasing atomic weight.1 Thanks to his creative genius, chemists now have a single document that contains enough information that explains almost all the properties of any element ever known to humankind.
From early childhood to death, Mendeleev dedicated his life to chemistry and science. Never did he turn his back to science. Even when he was not on the verge of great discoveries, Mendeleev was using his knowledge and expertise to further Russian industry and economy through scientific means. The Periodic Table of the Elements, though, was by far his greatest contribution to chemistry; however he could not achieve this without the help from previous chemists and alchemists. Even with the previous contributions made to such a remarkable achievement, Mendeleev is considered the father of the modern Periodic Table.
Chapter 02: Early Attempts at Periodic Table
Prior to Mendeleev, there were many attempts to organize the existing elements into a working order that would accurately portray their properties. Scientists like Johann Wolfgang Doberiener, Alexandre Beguyer de Chancourtois and John Newlands all found similarities between a few elements, and came close to organizing the elements accurately, but all failed.
Dobereiner developed the Law of Triads in 1829, which stated that the middle element in a triad (three consecutive elements in a column) had an atomic weight that was the average of the other two elements.2 Dobereiner’s work encouraged another chemist, Peter Kremers of Cologne, Germany, to study the law of triads. Kremers suggested some elements could belong to two triads, if the second triad was perpendicular to the first.3
In 1862, de Chancourtois published all the known elements, and displayed them in a helical graph wrapped around a cylinder, where elements with similar properties would be found on the same vertical line. His work was largely ignored until Mendeleev published his table. 4
John Newlands, an English chemist, arranged the 62 known elements in order of increasing atomic weights, and noticed that after every 8 elements, similar properties reoccurred. In 1863, Newlands proposed his Law of Octaves, which stated that “elements exhibit similar behaviours to the eighth element following it in the table”. 5
All these chemists had the right ideas but were not complete in their ideas. Only in 1869, did Dmitri Mendeleev get it right, when he proposed arranging the elements by atomic weights and properties.
Dmitri Ivanovich Mendeleev was born and raised in Tobolsk, Russia, as the youngest child in a family with 17 children. Dmitri’s father, Ivan Pavlovich Mendeleev, worked as the Director of the Tobolsk High School, where Dmitri himself attended and graduated from in 1850. His mother, Mariya Dmitrievna Mendeleev operated a glass factory owned by his family, during his childhood.6
Mendeleev was a very well educated person, who had a tremendous amount of interest in chemistry, an interest that was nurtured by his mother. Throughout his childhood, Mendeleev’s mother offered him special favours. From the beginning, his mother began saving money, little by little, so that he could one day be able to go to university. She also allowed him to go with her to work and observe the chemist who worked at the factory, and learn about glass making from him. This special attention by his mother, combined with his early influences towards chemistry only increased his love for learning and science.
Throughout his educational career, Mendeleev received many awards and had many achievements, including receiving the gold medal for natural sciences in 1855 from the University of St. Petersburg’s Physics and Mathematical Department.
Mendeleev not only studied and researched chemistry, he also wrote books about it. Among his more notable books (and also his first) was Organic Chemisrty, published in 1861, when he was only 27. Another famous book of Mendeleev’s was Fundamentals of Chemistry, published in 1868, which explained his basis for the periodic law.7 His books eventually gained enough recognition to become standard chemistry textbooks in Russian schools, and even to this day, many of the ideas and concepts discussed by Mendeleev in these books continue to find a place in Russian schools.8
Between 1859 and 1861, Mendeleev worked with R. W. Bunsen at Heidelberg University. Bunsen later went on to invent the Bunsen burner.9
Mendeleev was a very well revered chemist around the world. During his lifetime, he received more than 130 honorary degrees and titles from Russian and foreign academies, learned societies and educational establishments. Some of his more prestigious honorary degrees were received from the University of Oxford and the University of Cambridge (in the United Kingdom) in 1904. In 1905, Mendeleev received among the highest awards possible to a chemist; the Copley Award, given to him by the Royal Society, in London, England.10 The one award, which would have cemented him amongst the greatest chemists and scientists of all-time, was the Nobel Prize, which he never won, but came within one vote of winning in 1906.11
Creation of Modern Periodic Table
While teaching as a Professor of Chemistry at the University of St. Petersburg between 1857 and 1890, Mendeleev felt the need to bring the same kind of order to inorganic chemistry that organic chemistry was gaining through the Theory of Molecular Structure.12 Like many other chemists, Mendeleev believed the best way to organize the existing elements was to place them in increasing order according to their atomic weight.13 Mendeleev based his periodic table on the ‘four aspects of matter’, which were isomorphism, specific volumes of similar compounds or elements, composition of compound salts, and relations among atomic weights.14 Naturally, the easiest of the ‘four aspects of matter’ on which to base his table on were the relations among atomic weight b
Once Mendeleev completed his table, he learned that the elements did not have to be artificially grouped according to familiar properties, because they naturally formed their own groups. Mendeleev left some blank spaces on his original periodic table, because he believed that there were elements that belonged in the empty spaces that had not been discovered yet.15 Mendeleev, however, did accurately predict the density, radii, combining ratios with oxygen as well as some other properties of some unknown elements because of the properties of the elements surrounding those blank spaces. His predictions were later confirmed by the discovery of these elements.16 His three most accurate predictions turned out to be those of germanium, gallium, and scandium, which had almost the exact quantitative properties predicted by Mendeleev.
The official discovery date of the periodic table is dated as February 17th, 1869. Mendeleev did not even call the table ‘The Periodic Table’, but rather, he named it ‘practical experience with a system of elements based on their atomic weight and chemical similarity’.17 When presenting his concept for his version of the Periodic Table to the Russian Chemical Society, Mendeleev took some bold points to his colleagues, like, “the magnitude of the atomic weight determines the character of the element, just as the magnitude of the molecule determines the character of a compound body”.18 It was statements like these that his colleagues at first did not accept. Once his predictions came true, though, more and more chemists and scientists began to accept his model of organized elements.
How Periodic Table Became So Successful
Even with the changes that Chemistry has gone through over the course of the past 100 years, i.e., Quantum Theory, the basic structure and concept of the periodic table has remained the same and it is safe to say that the periodic table will continue to remain relatively the same over the next 100 years.
Prior to Mendeleev, chemistry and alchemy went hundreds, if not thousands of years with the knowledge of only 63 elements, but when the periodic table was discovered, the world was enlightened to another 55 elements over the course of the next 150 years.
The Periodic Table, from its inception into the scientific world, has become a vital tool for chemists and budding-chemists alike. Without it, students learning chemistry would be forced to learn all 118 elements and all their relevant properties. Memorizing the periodic table and all its properties would become a course all on its own. However, thanks to the genius of Dmitri Mendeleev, that is not necessary, anyone who wants to know almost anything about any element can simply look to the periodic table for the desired information.
Winning over the scientific community wasn’t easy for Mendeleev when he first introduced his proposal for an organization of the existing elements, but when he was proved right in his predictions of gallium, germanium and scandium, not only did he cause the scientific community to reconsider their scepticism, but he discovered something that would be the basis of future study for many years to come.
Its Modifications since Mendeleev
Not every scientist is totally correct in any radical new concept introduced. There will always be others who come along and study a previous discovery, only to realize that there was either some sort of mistake, or something overlooked, or there may just be a better way of doing something. This was no different for Mendeleev. In 1894, William Ramsay of University College London, discovered argon (Ar), and over the next few years, he also discovered Helium (He), Krypton (Kr), Neon (Ne) and Xenon (Xe).19 Ramsay had essentially discovered what are now known as the noble gases. They had received the name “noble” because they seemed to stand out from almost all the other elements, rarely, if ever, interacting with any of them. It was for this reason that they became difficult for chemists to add to the periodic table. Not only had they not been predicted by Mendeleev, but they didn’t even have a column in which to go. Only after 6 years of research and study, did chemists and physicists finally find a place for them on the periodic table, when they created a whole new column for them at the end. They were introduced between the halogens and the alkali metals.20
A
The last major changes made to the periodic table occurred around 1940, when chemist, Glenn Seaborg discovered the element, plutonium. This led him to the discovery of more trans-uranium elements (elements 94 through 102) and forced him to reconfigure the table to include the lanthanide and actinide series.23
Seaborg’s modifications were among the last major changes to the periodic table. Since then, it has remained relatively the same.
Description of Current Periodic Table
The periodic table as it looks today, contains 118 elements, and is organized into the different periods and groups, and was essentially created by Dmitri Mendeleev. It is also ordered in accordance to atomic numbers, where Hydrogen is the first element because of its one proton in the nucleus, and Ununoctium as the last element with 118 protons in the nucleus.
The periodic table also contains almost all quantitative properties of the elements, including such important ones as atomic number, mass number, boiling point, first ionization potential, electro negativity, oxidation states, electron configuration and much more.
Other Important Contributions by Mendeleev
Dmitri Mendeleev was not a one dimensional man. He was not only interested in applying his knowledge to the vast, wonderful world of chemistry; he also showed much interest and knowledge in other subjects, including writing, physics, agriculture, aeronautics, chemical technology, economics, meteorology, and national education.24
Among Mendeleev’s contributions to other subjects, his most notable ones outside of chemistry came in physics. Mendeleev is much responsible for the theory behind the solvation of ions. He also indicated that there is the existence of an ‘absolute boiling point’, later named critical temperature. Mendeleev is also responsible for the equation of state for one mole of an ideal gas.25
In 1890, Mendeleev invented new smokeless gunpowder called ‘pyrocollodium’ and in 1892, he began manufacturing the product.26
His scientific investigations were closely linked to the economic development of Russia. As a prominent public figure at the time, he constantly spoke out for the industrial development and economic independence of Russia.27
In 1865, Mendeleev managed a farm where he used his chemical knowledge to increase his crop yield, something which he then tried to apply to the Russian agriculture industry to help with their food production.
In 1867, Mendeleev was sent to Paris for the Paris Exposition. While in Paris, he studied the French chemical industry. The knowledge he gained from their industry allowed him to apply similar knowledge to Russia’s industry, and eventually led to an overall improvement in their soda industry.28
Mendeleev had so many different influences on Russian society, and on the world, that it is almost impossible to track them all.
Concluding Thoughts
After living in St. Petersburg at the turn of the century, Mendeleev caught a bad case of pneumonia and never recovered. He died on January 07th, 1907.29
Mendeleev truly was a man of science. His contributions in science reached far and wide. Without a doubt, Dmitri Mendeleev is one of the greatest, if not the greatest contributor to the world of Chemistry. Without his accomplishments, the world would be a very different place. It is in part to him, that any technology exists today. Up to 1869, there were only 63 known elements, and after his discovery of organizing the known elements by increasing atomic weight, we had reached 118 by 1940. With his discovery of the Periodic Table, Mendeleev truly has cemented himself as one of the greatest scientists ever, putting him in an exclusive list, which would include Albert Einstein, Thomas Edison, Niels Bohr, Isaac Newton and Galileo Galilei.
