Chapter 8: The d- and f-Block Elements

Focusing on Chapter 8: The d- and f-Block Elements from the Class 12 CBSE NCERT Chemistry textbook, here are some of the most frequently asked questions:

1. Lanthanoid Contraction: What is meant by 'lanthanoid contraction'?

2. Variable Oxidation States: Why do transition elements show variable oxidation states?

3. Electronic Configuration: Write down the electronic configuration of:

   • Cr³⁺
   • Pm³⁺
   • Cu⁺
   • Ce⁴⁺
   • Co²⁺
   • Lu²⁺
   • Mn²⁺
   • Th⁴⁺

4. Preparation of Potassium Permanganate: Describe the preparation of potassium permanganate from pyrolusite ore.

5. Chromate and Dichromate Ions: Discuss the interconversion between chromate and dichromate ions in aqueous solution.

6. Catalytic Properties: Explain why transition metals and their compounds exhibit catalytic properties.

7. Colour of Transition Metal Ions: Why are transition metal ions coloured? Illustrate with an example.

8. Actinoid Contraction: What is actinoid contraction? How does it compare with lanthanoid contraction?

9. Oxidation States of Lanthanoids: Which oxidation state is most common among lanthanoids and why?

10. Magnetic Properties: Discuss the magnetic properties of transition metal complexes.

These questions cover key concepts from the chapter and are often emphasized in exams. For detailed solutions and additional practice, you may refer to the provided links.