The d orbitals of transition elements protrude to the periphery of an atom more than other orbitals, making them more influenced by the surroundings and affecting the atoms or molecules in their vicinity.

Zn, Cd, Hg, and Cn are not considered transition elements as their d orbitals are completely filled in both the ground state and common oxidation states, deviating from the characteristic incompletely filled d orbitals of transition elements.

Cr has a configuration of 3d⁵ 4s¹ instead of 3d⁴ 4s², and Cu has 3d¹⁰ 4s¹ instead of 3d⁹ 4s². The small energy gap between 3d and 4s orbitals prevents electrons from entering the 3d orbitals, contributing to these unique ...

Exceptions arise due to minimal energy differences between (n-1)d and ns orbitals. Half and completely filled sets of orbitals are more stable, leading to anomalies like Cr having a configuration of 3d⁵ 4s¹ instead of 3d⁴ 4s².

The general electronic configuration is (n-1)d¹⁻¹⁰ ns¹⁻², but Pd deviates with a configuration of 4d¹⁰ 5s⁰ due to its specific energy considerations.