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 58.71 amu. Give reason for the same.

Answer 1

there is an anomaly because to remain in same chemical properties

Answer 2

This was a drawback in Mendeleev's periodic table.