d and f BLOCK ELEMENTS

What is the main factor contributing to the stability of the +2 oxidation state for Zinc (Zn)?

• Its low ionisation enthalpies
• Its high melting point
• Its metallic bonding
• The attainment of the stable, filled d10 electron configuration

Why is the E°(Fe3+/Fe2+) value positive, indicating Fe3+ is an oxidising agent?

• Fe2+ is larger than Fe3+
• Fe3+ is more hydrated than Fe2+
• Fe2+ (d6) is relatively stable, making its oxidation to Fe3+ (d5) favorable
• Fe3+ (d5) is relatively stable, making its reduction to Fe2+ (d6) favorable

Which of the following best describes the relationship between the stability of an oxidation state and its E°(M3+/M2+) value?

• A more positive E°(M3+/M2+) indicates the M2+ state is more stable relative to M3+
• There is no relationship
• Stability cannot be determined from E° values
• A more negative E°(M3+/M2+) indicates the M2+ state is more stable relative to M3+

Why do transition metals often form coloured ions in aqueous solution?

• Because they are large ions
• Because they form precipitates
• Because they have high charge densities
• Due to d-d transitions absorbing visible light

What is the primary reason for the catalytic activity of transition metals and their compounds?

• They are highly reactive metals
• They have high melting points
• They are good conductors of electricity
• Their ability to adopt multiple oxidation states and form complexes