Electronic Configuration of f-Block Elements

The electronic configuration of f-block elements is unique because it involves the filling of the 4f and 5f orbitals. For lanthanides, the electrons are added to the 4f orbital, while for actinides, the electrons are added to the 5f orbital.

For example, the general electronic configuration of lanthanides is [Xe] 4f^1-14 5d^0-1 6s², and for actinides, it is [Rn] 5f^1-14 6d^0-1 7s². This unique filling of f-orbitals gives rise to their special properties, such as variable oxidation states and complex formation.