Answer:- i. Strong field ligands: Those ligands which cause larger splitting of d orbitals and favour pairing of electrons are called strong field ligands. Strong field ligands contain C, N, and P as donor atoms. e.g. CN– , NCS– , CO, NH3, EDTA, en (ethylenediammine). ii. Weak field ligands: Those ligands which cause lower splitting of d orbitals i.e., ∆° parameter is smaller compared to the energy required for the pairing of electrons are called weak field ligands. Weak field ligands contain halogen, O, and S as donor atoms. e.g. F– , Cl– , Br– , I–, SCN–, `\”C\”_2\”O\”_4^{2-}`.