Dmitri Mendeleev is the scientist famous for the formulation of the periodic table. In 1869, he organized elements according to their atomic mass and shared properties, allowing for the prediction of undiscovered elements. Mendeleev's periodic table was groundbreaking, as it highlighted periodic trends and reactivity among elements. His work laid the groundwork for modern chemistry and the development of the periodic table we use today, which is organized by atomic number rather than mass.