Julius Lothar Meyer
In 1869, Dmitri Mendeleev published a periodic table of all known elements (he predicted several new elements to complete the table, and corrected some atomic weights). A few months later, Meyer published a revised and expanded version of his 1864 table independently, which was similar to that published by Mendeleev (Meyer had been sent a copy of Mendeleev's table earlier; Mendeleev had sent it to many well-known chemists of his day) and a paper showing graphically the periodicity of the elements as a function of atomic weight. Meyer, as well as other chemists, was doubtful about Mendeleev's periodic law, and he criticized Mendeleev for "changing existing elements' atomic weights, only regarding possibility of periodical law in its structure". However, Mendeleev's work received significant support, when the new elements were found as predicted and atomic weights accordingly.
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."