d and f BLOCK ELEMENTS

Which factor primarily determines why only oxidizing acids react with copper?

• The low reactivity of copper.
• The high concentration of the acid.
• The negative E° value of the Cu2+/Cu couple.
• The positive E° value of the Cu2+/Cu couple.

If a metal's E°(M2+/M) value is calculated to be more negative than its observed value, what might this imply about the factors considered in the calculation?

• The calculation is perfectly accurate.
• The calculation underestimates the energy cost.
• The calculation overestimates the energy gain.
• The calculation might overestimate the energy cost or underestimate the energy gain.

What role does crystal field stabilization energy (CFSE) play in the hydration of transition metal ions like Cu2+?

• It is the primary factor determining hydration enthalpy.
• It has no effect on hydration enthalpy.
• It only applies to high-spin complexes.
• It can influence the effective size and polarizability of the ion, affecting the hydration enthalpy.

Why is the sum of the first and second ionization enthalpies important for determining the M2+/M electrode potential trend?

• Because it determines the hydration enthalpy.
• Because it is always constant across the series.
• Because it represents the only energy change in the process.
• Because it represents a major energy cost in the process M(s) → M2+(aq).

Comparing the E°(M2+/M) values, which metal is expected to be the strongest reducing agent among the first transition series elements?

• The metal with the least negative E° value.
• The metal with a positive E° value.
• The metal with the E° value closest to zero.
• The metal with the most negative E° value.