State the merits of Mendeleev's classification of elements.

Merits of Mendeleev’s classification of elements:

1. Grouping of elements: He generalized the study of the elements then known to a study of mere eight groups.
2. Gaps of undiscovered elements: Mendeleev left some gaps in his periodic table for the subsequent inclusion of elements not known at that time.
3. Prediction of properties of undiscovered elements: He predicted the properties of then unknown elements based on the properties of elements lying adjacent to the vacant slots.
4. Incorrect atomic mass corrected: He was able to correct the atomic mass of elements like gold and platinum by placing these elements strictly based on the similarities in their properties.