Why do ions with partly filled d orbitals among transition elements exhibit characteristic properties like multiple oxidation states, colored ions, and complex formation?

Ions with partly filled d orbitals among transition elements exhibit characteristic properties due to the ability of these orbitals to undergo electron rearrangement. The presence of partially filled d orbitals allows for multiple oxidation states as electrons can be easily gained or lost. The transition metal ions absorb and emit specific wavelengths of light, leading to colored ions. Additionally, the partially filled d orbitals enable the formation of complex compounds with ligands, where molecules or ions coordinate with the central metal ion. These unique properties arise from the flexibility of d orbitals to accommodate different electron configurations, contributing to the diverse chemistry of transition elements.