Question

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

• 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 with increase in atomic number
• D. for transition elements the rf-subshells are filled with electrons monotonically with increase in atomic number

Answer 1

Answer: (D)

(a) Correct statement According to Moseley- 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 monotonically, regularity break at chromium and copper