Question

In Mendeleev's periodic table, the elements were arranged in the increasing order of their atomic masses. However, cobalt with atomic mass of 58.93 amu was placed before nickel having an atomic mass of 58.69 amu. Reason for the same is that :

• A. the elements with similar size can be grouped together
• B. the elements with different properties can be grouped together
• C. the elements with similar properties can not be grouped together
• D. the elements with similar properties can be grouped together

Answer 1

The correct option is D the elements with similar properties can be grouped together

According to Mendeleev's classification, the properties of elements are the periodic function of their atomic masses and there is a periodic recurrence of elements with similar physical and chemical properties.

Noble gas being inert, could be placed in a separate group without disturbing the original order.

Hence the correct option is D.