Dmitri Mendeleev
Unaware of the earlier work on periodic tables going on in the 1860s, he made the following table:
By adding additional elements following this pattern, Mendeleev developed his extended version of the periodic table. On 6 March 1869, he made a formal presentation to the Russian Chemical Society, titled "The Dependence between the Properties of the Atomic Weights of the Elements", which described elements according to both atomic weight (now called "relative atomic mass") and valence. This presentation stated that
Theodore Gray
After amassing thousands of samples of elements, he assembled them into a four-legged physical table representing the periodic table. The finished table was awarded the 2011 ACS Grady Stack Award for Interpreting Chemistry for the Public, as well as the 2002 Ig Nobel Award for Chemistry. Gray's love of the periodic table would lead him to team up with photographer Nick Mann in creating "The Elements: A Visual Exploration of Every Known Atom in the Universe" and "Elements Vault."