d and f BLOCK ELEMENTS

Why do transition elements generally have high enthalpies of fusion?

• They have low atomic masses.
• They form weak van der Waals forces.
• The strong metallic bonds formed by both s and d electrons require significant energy to break.
• They have simple cubic structures.

What is the main reason for the variable oxidation states in transition metals?

• High electronegativity
• Low ionization energies
• Similar energies of (n-1)d and ns orbitals.
• Large atomic radii

Which of the following is NOT a typical property of transition elements?

• Variable oxidation states
• Formation of colored compounds
• Paramagnetism
• Forming compounds that are predominantly ionic.

What happens when Potassium Dichromate reacts with H₂S in acidic medium?

• Cr₂O₇²⁻ is oxidized to CrO₄²⁻.
• Cr₂O₇²⁻ is reduced to Cr³⁺, and H₂S is oxidized to S or SO₂.
• H₂S reduces Cr₂O₇²⁻ to metallic Cr.
• Cr₂O₇²⁻ precipitates sulfur.

What happens when Potassium Dichromate reacts with an iodide ion in acidic medium?

• Cr₂O₇²⁻ is oxidized to CrO₄²⁻.
• Cr₂O₇²⁻ is reduced to Cr³⁺, and I⁻ is oxidized to I₂.
• I⁻ reduces Cr₂O₇²⁻ to metallic Cr.
• No reaction occurs.