The electronic configuration of a transition metal ion plays a crucial role in its reactivity with ligands in complex formation reactions. Transition metals have partially filled d orbitals, which allow them to accept electron pairs from ligands and form coordination complexes. The reactivity of a transition metal ion with ligands depends on several factors, including the metal's oxidation state, the number of available d orbitals, and the nature of the ligands.1. Oxidation state: The oxidation state of a transition metal ion affects its reactivity with ligands. Higher oxidation states generally result in a stronger attraction between the metal ion and the ligand, leading to more stable complexes. For example, Fe III forms more stable complexes with ligands than Fe II due to its higher oxidation state.2. Number of available d orbitals: The number of available d orbitals for bonding with ligands also influences the reactivity of a transition metal ion. Transition metals with more available d orbitals can form a greater variety of complexes with different coordination numbers and geometries. For example, Cu II has a d9 electronic configuration and can form square planar and octahedral complexes, while Zn II has a d10 configuration and typically forms only tetrahedral complexes.3. Nature of the ligands: The nature of the ligands also affects the reactivity of a transition metal ion in complex formation reactions. Some ligands, such as cyanide CN- and ethylenediamine en , are strong-field ligands that cause a large splitting of the d orbitals, leading to the formation of low-spin complexes. Other ligands, like halides Cl-, Br-, I- , are weak-field ligands that cause a smaller splitting of the d orbitals, resulting in high-spin complexes.Examples of transition metal ions and their corresponding ligands:1. [Fe CN 6]^3-: In this complex, Fe III has a d5 electronic configuration and forms a low-spin octahedral complex with six cyanide ligands. The strong-field ligand CN- causes a large splitting of the d orbitals, stabilizing the complex.2. [Cu NH3 4]^2+: In this complex, Cu II has a d9 electronic configuration and forms a square planar complex with four ammonia ligands. The ammonia ligands are moderately strong-field ligands, leading to a stable complex.3. [Zn H2O 6]^2+: In this complex, Zn II has a d10 electronic configuration and forms a tetrahedral complex with six water ligands. The water ligands are weak-field ligands, resulting in a high-spin complex.In summary, the electronic configuration of a transition metal ion affects its reactivity with ligands in complex formation reactions by influencing the metal's oxidation state, the number of available d orbitals, and the nature of the ligands. These factors determine the stability, geometry, and spin state of the resulting complexes.