d and f BLOCK ELEMENTS

Why are Mn²⁺ compounds generally more stable than Fe²⁺ compounds towards oxidation to the +3 state?

• Fe²⁺ has a more stable electron configuration.
• The atomic size of Mn is larger.
• The half-filled d orbital in Mn²⁺ (3d⁵) provides extra stability.
• Mn has a lower electronegativity.

What is the electronic configuration of Cr³⁺?

• [Ar] 3d⁵
• [Ar] 3d³
• [Ar] 4s¹ 3d⁵
• [Ar] 3d⁴ 4s²

What is the primary role of the copper co-catalyst often used with PdCl2 in the Wacker process?

• To directly oxidize ethylene
• To act as the main catalyst
• To facilitate the regeneration of the active Pd(II) catalyst
• To provide chloride ions

What is the main factor that determines the color observed in a solution of a transition metal complex?

• The color of the metal atoms
• Reflection of all wavelengths
• The specific wavelengths of light absorbed by d-d transitions
• Emission of light from the complex

How does the reactivity of first series transition metals with water generally compare (excluding copper)?

• They are completely inert
• They react easily, producing hydrogen gas and metal hydroxides
• They only react with steam
• They form passive oxide layers