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

Options

A. For transition elements, the `d` subshells are filled with electrons monotonically with the increase in atomic number.
B. The first ionization energies of elements along a period do not vary in a regular manner with the increase in atomic number.
C. Nonmetallic elements are lesser in number than metallic elements.
D. The properties of element ate the periodic functions of tehir atomic numbers.

Answer

A

Explanation

Because there are deviations, for example, at `Cr (Z = 24)`and `Cu(Z = 29)`, in the first transition series. `Cr` has configuration `[Ar]3d^(5)4s^(1)` instead of `[Ar]3d^(4)5s^(2).Cu` has configuration `[Ar]3d^(10)4s^(1)` instead of `[Ar]3d^(9)4s^(2)`.