d and f BLOCK ELEMENTS

How does the concept of exchange energy relate to the stability of the d5 configuration in Mn2+?

• Exchange energy is minimized in the d5 configuration.
• Exchange energy is irrelevant for transition metal ions.
• Exchange energy only applies to paired electrons.
• Maximum exchange energy is achieved in the d5 configuration, leading to enhanced stability.

What would be the expected effect on the E°(M2+/M) value if the hydration enthalpy of M2+ becomes more negative (larger in magnitude)?

• The E°(M2+/M) value would become less negative.
• The E°(M2+/M) value would remain unchanged.
• The E°(M2+/M) value would become positive.
• The E°(M2+/M) value would become more negative.

Why is the E°(M2+/M) value for Zn more negative than that for Cu?

• Zn has a lower atomic mass.
• Cu has a more negative hydration enthalpy.
• Zn has lower ionization enthalpies.
• Zn2+ has a stable d10 configuration, providing extra stability that outweighs the energy costs better than for Cu.

What is the primary reason Cr2+ (d4) is a better reducing agent than Mn2+ (d5)?

• Cr2+ has a higher charge.
• Mn2+ is more stable than Cr2+.
• Cr2+ has a lower atomic number.
• Cr2+ achieves greater stability by losing an electron to reach the d3 configuration with a half-filled t2g level, compared to Mn2+ which is already stable.

Which statement best explains why the E°(M2+/M) value is a good indicator of a metal's reducing power?

• A more positive E° indicates a greater tendency for the metal to lose electrons.
• A positive E° indicates the metal cannot act as a reducing agent.
• The E° value is unrelated to reducing power.
• A more negative E° indicates a greater tendency for the metal to lose electrons and be oxidized.