The United Nations announced 2019 as the International Year of the Periodic Table of Chemical Elements to highlight its first publication in 1869. The periodic table as we know it today was designed for the first time by Russian scientist Dmitri Ivanovich Mendeleev.
The periodic table is not only a typical wall decoration in high school science classrooms, it is also an exceptional tool for scientists to understand, and even predict, the properties of all elements.
The UN announcement will help raise the profile of how chemistry can provide solutions to global challenges in agriculture, education, energy and health.
This year marks the 150th anniversary of the first publication of the periodic table by Mendeleev. Since its inception, the periodic table has been at the center of many vivid debates and is now regarded as "one of the most important and influential achievements of modern science, reflecting the essence not only of chemistry, but also of physics, biology and other disciplines . "
Mendeleev's genius lies in the recognition that, at the time, not all elements were known yet, so he left gaps in the table for undiscovered elements. At that time, only 63 elements had been identified. Yet the properties of five other elements (the gaps brilliantly added to complete the table) could already be determined using the table.
Mendeleev's desk has been in the limelight for decades, but a few other scientists tried before he organized all known elements. Already in 1789, Antoine Lavoisier established a list of 33 elements and tried to unravel the secrets of the chemical elements and classify them according to their properties.
Scientists such as Alexandre-Emile Béguyer de Chancourtois, John Newlands, and Julius Lothar Meyer proposed a different way of organizing the elements. A propeller, a chart, a cylinder and even a spiral were proposed to visualize the arrangement of the elements, but none seemed to be a perfect fit.
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The discovery of some of these elements in the following years confirmed Mendeleev's predictions and revealed the brilliance of the Periodic Law, as Mendeleev called his table.
Fifty-five elements were discovered since Mendeleev's first scheme and they were all incorporated into the existing classification according to their atomic mass. Of course, they have the properties provided by the incomplete table, which explains why Mendeleev's attempt to order the elements was so successful and survived the centuries.
Element 101 was named mendelévius to pay homage to Mendeleev's contributions. This is indeed an even rarer distinction than winning the Nobel Prize: only 50 scientists have elements with names, while 180 chemists received a Nobel Prize in chemistry.
By 2016, four elements still needed to be discovered according to the gaps in the periodic table. With the addition of nihonium, moscovium, tennessine and oganesson, the periodic table is complete.
Or is it?
Nominating 2019 as the International Year of the Periodic Table can draw the public's attention to the importance of chemistry in our lives, stimulate our curiosity about science and encourage scientists' interest in finding even more elements.
Alexandra Gelle, PhD Candidate in Chemistry, McGill University, The Canadian Press
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