The d-and f-Block Elements — Important Questions

Formation of colored compounds, Variable oxidation states, Catalytic properties, Paramagnetism

Transition elements show colored compounds due to d-d transitions, variable oxidation states due to similar energies of ns and (n-1)d orbitals, catalytic properties due to multiple oxidation states, and paramagnetism due to unpaired electrons. They are not highly reactive with water like alkali metals.

K₂Cr₂O₇ (Potassium dichromate), KMnO₄ (Potassium permanganate)

K₂Cr₂O₇ and KMnO₄ are strong oxidizing agents because they contain metals (Cr and Mn) in high oxidation states (+6 and +7 respectively) that can be easily reduced. FeSO₄ and CuSO₄ are not typically used as oxidizing agents.

3.87 BM

The magnetic moment is calculated using the spin-only formula: μ = √[n(n+2)] BM, where n is the number of unpaired electrons. For n=3: μ = √[3(3+2)] = √15 = 3.87 BM.

Lanthanoids and actinoids

The f-block consists of lanthanoids (4f series, Ce to Lu) and actinoids (5f series, Th to Lr). These elements have partially filled f-orbitals and are also called inner transition elements.