First periodic table, 6 MARCH 1869

Although other researchers had previously discovered the periodicity of elements, Dmitri Mendeleev introduced the first periodic table on March 6, 1869.

Russian chemist and professor Mendeleev created his own chemical textbooks to suit his demands. He tried to categorize the elements according to their chemical characteristics while writing a book on inorganic chemistry and discovered patterns that inspired him to postulate his periodic table. In 1869, his table was included in his textbook, The Principles of Chemical.

History records Mendeleev as being unaware of similar studies that a few other scientists had been working on in the 1860s.The Relationship between the Characteristics of the Atomic Weights of the Elements" was the title of a formal presentation he gave to the Russian Chemical Society in March 1869. It explained elements in terms of both atomic weight and valence.

A few months later, a nearly identical table was published by German chemist Julius Lothar Meyer. While Meyer and Mendeleev are frequently credited with creating the table, Mendeleev is frequently given the most of the credit for predicting the table's eight elements. He named them using the Sanskrit prefixes eka, dvi, and tri (one, two, and three).

Mendeleev's forecast that there will be more elements was initially disregarded, but when the elements Ga (gallium) and Ge (germanium), which fit exactly into his predictions and table and were discovered in 1875 and 1886, respectively, he was shown to be correct.