Who Invented the Periodic Table?

Original version of the Periodic Table of elements published in 1869 by the Russian chemist Dmitri Mendeleyev.
Original version of the Periodic Table of elements published in 1869 by the Russian chemist Dmitri Mendeleyev. Clive Streeter / Getty Images

Do you know who described the first periodic table of the elements that organized the elements by increasing atomic weight and according to trends in their properties?  

If you answered "Dmitri Mendeleev" then you might be incorrect. The actual inventor of the periodic table is someone rarely mentioned in chemistry history books: de Chancourtois.

History of the Periodic Table

Most people think Mendeleev invented the modern periodic table. Dmitri Mendeleev presented his periodic table of the elements based on increasing atomic weight on March 6, 1869, in a presentation to the Russian Chemical Society. While Mendeleev's table was the first to gain some acceptance in the scientific community, it was not the first table of its kind.

Some elements were known since ancient time, such as gold, sulfur, and carbon. Alchemists began to discover and identify new elements in the 17th century. By the beginning of the 19th century, about 47 elements had been discovered, providing enough data for chemists to begin to see patterns. John Newlands had published his Law of Octaves in 1865. The Law of Octaves had two elements in one box and did not allow space for undiscovered elements, so it was criticized and did not gain recognition.

A year earlier (1864) Lothar Meyer published a periodic table which described the placement of 28 elements. Meyer's periodic table ordered the elements into groups arranged in order of their atomic weights. His periodic table arranged the elements into six families according to their valence, which was the first attempt to classify the elements according to this property.

While many people are aware of Meyer's contribution to the understanding of element periodicity and the development of the periodic table, many have not heard of Alexandre-Emile Béguyer de Chancourtois. De Chancourtois was the first scientist to arrange the chemical elements in order of their atomic weights. In 1862 (five years before Mendeleev), de Chancourtois presented a paper describing his arrangement of the elements to the French Academy of Sciences. The paper was published in the Academy's journal, Comptes Rendus, but without the actual table. The periodic table did appear in another publication, but it was not as widely read as the Academy's journal. De Chancourtois was a geologist and his paper primarily dealt with geological concepts, so his periodic table did not gain the attention of the chemists of the day.

Difference From the Modern Periodic Table

Both de Chancourtois and Mendeleev organized elements by increasing atomic weight. This makes sense, because the structure of the atom was not understood at the time, so the concepts of protons and isotopes had yet to be described. The modern periodic table orders the elements according to increasing atomic number rather than increasing atomic weight. For the most part, this doesn't change the order of the elements, but it's an important distinction between older and modern tables. The earlier tables were true periodic tables since they grouped the elements according to ​the periodicity of their chemical and physical properties.