Question

In certain pair of elements, the increasing order of atomic masses was not obeyed. Is it true according to Mendeleev's periodic table?

• A. True
• B. False

Answer 1

The correct option is A True

In few pair of elements, the increasing order of atomic masses was not obeyed. In these, Mendeleev placed elements according to their similar properties and not in increasing order of their atomic masses. For example, the atomic mass of argon is 39.9 and that of potassium 39.1, but argon is placed before potassium in the periodic table.