Question:
The statement that is not correct for periodic classification of elements is:
(i) The properties of elements are periodic function of their atomic numbers.
(ii) Non-metallic elements are less in number than metallic elements.
(iii) For transition elements, the 3d-orbitals are filled with electrons after
3p-orbitals and before 4s-orbitals.
(iv) The first ionisation enthalpies of elements generally increase with
increase in atomic number as we go along a period.
Solution:
Option (iii) For transition elements, the 3d-orbitals are filled with electrons after
3p-orbitals and before 4s-orbitals. is the answer.