d and f BLOCK ELEMENTS

Why do some transition metal complexes exhibit magnetic moments significantly different from the 'spin-only' value calculated using μ = √[n(n+2)] BM?

• Because the formula is inaccurate.
• Because temperature affects magnetic moments.
• Because the complexes are colored.
• Because the 'spin-only' formula neglects the contribution of orbital angular momentum, which can be significant in certain complexes, especially those with unfilled t2g orbitals.

Why does the stability of higher oxidation states generally increase from the first to the second and third transition series?

• Because heavier elements are more reactive.
• Because heavier elements have more electrons.
• Because heavier elements are metals.
• Because the higher nuclear charge in heavier elements makes it easier to hold onto electrons in high oxidation states, and relativistic effects also play a role.

Why do tetrahedral complexes of transition metals almost always exhibit high-spin configurations?

• Because tetrahedral complexes are less stable.
• Because tetrahedral complexes have fewer ligands.
• Because the crystal field splitting energy (Δ_tet) in tetrahedral complexes is inherently much smaller than the typical electron pairing energy (P).
• Because tetrahedral complexes are formed by weak field ligands.

Why are high-spin complexes generally formed more readily with weak field ligands like H2O compared to strong field ligands like CN-?

• Because weak field ligands are smaller.
• Because weak field ligands are more electronegative.
• Because the crystal field splitting energy (Δ) produced by weak field ligands is smaller than the electron pairing energy (P), making it energetically favorable to occupy higher energy orbitals rather than pair.
• Because strong field ligands are better at donating electrons.

Why do transition metal complexes often exhibit different colors in solution compared to their solid-state forms?

• Because solutions are transparent.
• Because the metal changes oxidation state.
• Because the concentration changes.
• Because the crystal field environment (ligands and geometry) differs between solution and solid state, altering the d-orbital splitting and the wavelengths of light absorbed.