The Science History Institute joins UNESCO in celebrating 2019 as the International Year of the Periodic Table.
Marking the 150th anniversary of one of the most significant achievements in science, the International Year of the Periodic Table (IYPT2019) provides an ideal opportunity for the Institute to showcase our collections, programs and events, and research activities, and to engage in a global conversation about the importance of science. Join the celebration by following #IYPT2019 on Facebook, Twitter, and Instagram.
In 1869 Russian chemist Dmitri Ivanovich Mendeleev (1834–1907)—recognized as the father of the periodic table—created a simple chart categorizing the elements, which he included in his chemistry textbook titled Osnovy khimii (Principles of Chemistry). What set Mendeleev’s table apart from those of other chemists was not his organization of the 63 elements known at the time but his prediction that some elements were missing.
While ordering the elements by atomic weight, Mendeleev noticed patterns that revealed what came to be known as the periodic law. This discovery allowed him to accurately predict the existence of the yet-unknown elements and their location on the table. When gallium and germanium were discovered in 1875 and 1886, respectively, they fit perfectly into the corresponding missing spaces. There are now 118 elements on the periodic table, including mendelevium (chemical symbol Md and atomic number 101), identified in 1955 and named after Mendeleev.
Check out some of the (literal) twists on the periodic table found in our collections.