Dmitri Mendeleev
De Boisbaudran calculated the atomic mass of gallium as 69.86, close to the currently accepted value of 69.723. Unknown to Lecoq de Boisbaudran, the existence of gallium had been predicted during 1871 by Dmitri Mendeleev, who gave it the name "eka-aluminium". De Boisbaudran's discovery of gallium was significant support for Mendeleev's theory of the periodicity of the elements.