Question

Name two properties of the central metal ion which enable it to form stable complex entities.

Answer 1

1. High Charge Density (High Positive Charge/Small Size): A metal ion with a high positive charge and small ionic radius exerts a strong electrostatic attraction on ligands. This strong attraction promotes the formation of stable coordinate bonds. For example, Co³⁺ forms more stable complexes than Co²⁺ due to its higher charge density.
2. Availability of Vacant d-Orbitals: The central metal ion must have empty d-orbitals to accept lone pairs of electrons from ligands. Transition metals are particularly effective at forming complexes because they have partially filled d-orbitals that can participate in bonding.