The scientist who developed the periodic table is Dmitri Mendeleev. In 1869, Mendeleev presented his periodic table, organizing chemical elements based on their atomic weights and similar chemical properties. His work allowed for a systematic classification of elements, highlighting periodic trends and enabling predictions about undiscovered elements. Mendeleev's periodic table laid the foundation for modern chemistry by providing a framework for understanding elemental behavior. His foresight in leaving gaps for unknown elements demonstrated the dynamic nature of scientific progress, and the periodic table continues to be a fundamental tool for scientists today.