The statement that is not correct for periodic classification of elements is

Options

A. the properties of elements are the periodic functions of their atomic numbers
B. non-metallic elements are lesser in number than metallic elements
C. the first ionisation energies of elements along a period do not vary in a regular manner increase in atomic number
D. for transition elements of `d`- subshells are filled with electrons monotonically with increase in atomic number

Answer

D

Explanation

(a) Correct statement : According to Moseley's law, the properties of elements are the periodic function of their atomic numbers.
(b) Correct statement: The whole `s`-block, `d`- block, `f`- block and heavier `p`- block elements are metal.
(c) correct statement : Trend is not regular, Be has higher first ionisation energy than `B`, nitrogen has higher first ionisation energy than oxygen.
(d) Incorrect statement `d`- subshells are not filled monitonically, regularity break at chromium and copper.