10 public questions tagged with this topic.
Europium (Eu) shows +2 oxidation state due to the stability of half-filled 4f 7 configuration, along with the common +3 state.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Oxidation States and Colour and Magnetic Properties of d-Block
Cu + is common due to the stability of the 3d 10 configuration.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Lanthanoids - Electronic Configuration and Lanthanoid Contraction
Cerium (Ce) exhibits +4 oxidation state due to the stability of empty 4f orbitals (4f 0 ).
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Lanthanoids - Electronic Configuration and Lanthanoid Contraction
Lanthanoid contraction causes similar atomic radii of Zr (160 pm) and Hf (159 pm), making their separation difficult.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Lanthanoids - Electronic Configuration and Lanthanoid Contraction
Comparable energies of (n-1)d and ns orbitals allow for variable electron loss.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: General Properties of d-Block - Electronic Configuration and Trends
Transition metal complexes are typically colored due to d-d transitions.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Actinoids and Comparison of Lanthanoids and Actinoids
Actinoids are all radioactive, contrary to the incorrect option.
Ref: NCERT Class 12 Chemistry > Chapter 4: d and f Block Elements > Topic: Actinoids and Comparison of Lanthanoids and Actinoids
C in CO₂: +4. In CH₂O: x + 2(+1) + (-2) = 0, x = 0, which is lower.
Ref: NCERT Class 11 Chemistry > Chapter 7: Redox Reactions > Topic: Electrode Potential and Electrochemical Series and Galvanic Cells
The +4 oxidation state is most stable for S in group 16, forming SO₂ (gaseous, strong S=O bonds), more stable than O₂, SeO₂ (polymeric), or TeO₂ (solid).
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Modern Periodic Law and Present Form - Long Form Periodic Table
d-block elements exhibit variable valency due to partially filled d-orbitals. Cu (group 11) shows this, unlike Na (s-block), Al (p-block), or Kr (p-block, full).
Ref: NCERT Class 11 Chemistry > Chapter 3: Classification of Elements and Periodicity in Properties > Topic: Electronic Configuration and Types of Elements - s p d f Blocks
