Question

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

• A. The properties of elements are periodic function of their atomic numbers.
• B. Non-metallic elements are less in number than metallic elements.
• C. For transition elements, the \(3d\)-orbitals are filled with electrons after \(3p\)-orbitals and before \(4s\)-orbitals.
• D. The first ionisation enthalpies of elements generally increase with increase in atomic number as we go along a period.

Hint:

In the periodic table, the properties of elements are periodic functions of their atomic numbers. The order of filling orbitals for transition elements is \(4s\) before \(3d\), not the other way around.