Dmitri Mendeleev referred to his periodic table as the ‘Periodic Law’ or ‘Periodic Table of Elements’.
In 1869, Mendeleev arranged the known elements based on their atomic masses, and he noticed that elements with similar properties appeared at regular intervals when the elements were sorted in this manner. This observation led him to formulate what is now known as Mendeleev’s periodic law, which states that the properties of the elements are a periodic function of their atomic weights. Mendeleev’s work laid the foundation for modern chemistry and the organization of elements in the periodic table that we use today.