Provide an example of the strong and weak field ligands on the electron configuration of transition metals.

Strong field ligands cause greater splitting of d-orbitals, resulting in lower energy and fewer unpaired electrons in the electron configuration of transition metals. Weak field ligands cause less splitting, resulting in higher energy and more unpaired electrons.

For example, the strong field ligand CN- causes a large splitting of the d-orbitals, resulting in a low-spin complex with fewer unpaired electrons. This is because the CN- ligand donates electrons to the metal ion, causing the energy levels of the d-orbitals to decrease. As a result, the electrons pair up in the lower energy orbitals, leading to a low-spin complex.

On the other hand, the weak field ligand H2O causes a small splitting of the d-orbitals, resulting in a high-spin complex with more unpaired electrons. This is because the H2O ligand does not donate electrons to the metal ion, causing the energy levels of the d-orbitals to remain high. As a result, the electrons occupy the higher energy orbitals, leading to a high-spin complex.

Understanding the effect of strong and weak field ligands on the electron configuration of transition metals is important in predicting the properties and reactivity of coordination compounds.