Which best explains how Dmitri Mendeleev organized elements in his periodic table?

Dmitri Mendeleev organized elements in his Periodic Table primarily by increasing Atomic Mass and grouped them according to similar chemical properties. He noticed that elements with similar characteristics appeared at regular intervals, which led him to create a periodic pattern. Mendeleev also left gaps for undiscovered elements, predicting their properties based on the trends he observed. This innovative approach laid the foundation for the modern periodic table.