The Periodic Table was first introduced by the Russian scientist Dmitri Mendeleev. Originally from Siberia, Mendeleev studied science at St Petersburg University, where he graduated as a chemist in 1856. By 1863 he was a Professor of Chemistry. Mendeleev first revealed his arrangement of 63 elements into his Periodic Table in his book, Principles of Chemistry, which was published in 1869.
Mendeleev’s Periodic Table was compiled on the basis of arranging the elements in ascending order of atomic weight, and grouping them by similarity of properties. Not only did he arrange these elements, but he also forward thinking enough to predict that other elements would be discovered in the future, and left spaces in the table where he believed they might fit into the chemical framework.
Dmitri Mendeleev wasn’t the first scientist to try and organise chemical elements into order. Beguyer de Chancourtois, Newlands and Lothar Meyer had all also worked on arranging the elements, but Mendeleev’s work surpassed all their individual attempts at classification.
It wasn’t until British chemist Henry Moseley (1887-1915), began work on developing the application of X-ray spectra to study atomic structure that a more accurate positioning of elements could be attained. He was also able to include the Nobel Gases, which had yet to be discovered in Mendeleev’s time.
When Moseley discovered that atoms should be arranged according to atomic number rather than weight, as Mendeleev had believed, The Periodic Table began to take on the appearance we recognise today.
The Periodic Table has been adapted and improved many times since Mendeleev’s initial design, but it remains one of the most important discoveries in Science, and one of the most recognisable tools in Chemistry.
Dr Kathryn Bates is a graduate of archaeology and history. She has excavated across the world as an archaeologist, and tutored medieval history at Leicester University. She joined the administrative team at Oxford Open Learning twelve years ago. Alongside her distance learning work, Dr Bates is a bestselling novelist, and an itinerant creative writing tutor for primary school children.