The screening effect of d−electrons is
The correct option is D Less than p−electrons
Penetration describes the proximity of electrons in an orbital to the nucleus. Electrons that have greater penetration can get closer to the nucleus and effectively block out the charge from electrons that have less proximity and hence have higher screening effect.
For the same value of n, the order of penetrating power is
s>p>d. The screening effect also follows the same order.
Hence the screening effect of d-electron is less than p−electrons .