Final answer:
Dmitri Mendeleev provided an organizing principle (periodic table) that worked for all the known elements.
Step-by-step explanation:
Dmitri Mendeleev provided an organizing principle (periodic table) that worked for all the known elements.
In 1869, Mendeleev published a periodic table of the elements, arranging them according to increasing atomic mass. He also left gaps in the table for undiscovered elements, making bold predictions about their properties. When elements were later discovered that matched Mendeleev's predictions, his version of the periodic table gained favor.
Keywords: Dmitri Mendeleev, periodic table, elements, atomic mass, properties