question_answer 12)

Which important property did Mendeleev use to classify the elements in the periodic table and did he stick to that?

Answer:

Mendeleev took atomic masses of the elements as the basis of classification of elements. He presented a periodic law before classification. The periodic law can be stated in short that 'the properties of the elements are a periodic function of their atomic masses. He arranged the elements in the table in the increasing order of their atomic masses. A number of gaps were left in the table for unknown elements and their properties were predicted on the basis of periodic law. These properties helped the future scientists to discover unknown elements. However, there was violation of periodic law at a few places to give proper position to certain elements on the basis of properties. The position of these elements was justified when the periodic law was modified.