Which of the following statements is not correct for the periodic classification of elements?

Options

A. The properties of the elements are the periodic function of their atomic numbers.
B. Non-metallic elements are lesser in number than the metallic elements.
C. The first ionization energies of the elements along a period do not vary in a regular manner with increase in atomic number.
D. For transition elements, the d-electrons are filled monotonically with increase in atomic number. (e) Both (c) and (d).

Answer

D

Explanation

In general, electron are added one at a time to the (n-1) d orbitals in transition elements. However, because of extra stability of `d ^(5) and d ^(10)` configurations, two electrons appear to have entered the d-subshell due to shifting of one electron from ns to `(n-1)` d orbital.