Chapter Hub

The d- and f-Block Elements

The d- and f-block elements are studied through their position, electronic configuration, oxidation states, colours, magnetic behaviour, catalytic properties, and compound formation. The chapter connects periodic trends with observable properties such as coloured ions, variable valency, and paramagnetism. Transition elements are especially important because their partially filled d-orbitals allow variable oxidation states, complex formation, alloy formation, and catalytic activity. These properties are frequently tested through reasons, comparisons, trend-based questions, and application examples. The compounds potassium permanganate and potassium dichromate are important oxidising agents. Their preparation, colour changes, oxidation-state changes, and acidic-medium reactions are useful for reaction-based and observation-based CBSE questions. The f-block section focuses on lanthanoids and actinoids, especially lanthanoid contraction, common oxidation states, actinoid variability, and uses such as misch metal. Students should connect contraction and shielding with similarities in later elements and separation difficulties.