Palladium's transition metal properties

Steps:

• Locate palladium (atomic number 46) in period 5, group 10 of the periodic table.
• Identify it as a d-block transition metal.
• Recall transition metals exhibit variable oxidation states due to partial d-orbital filling.
• Note catalytic activity from incomplete d-subshells enabling varied reaction intermediates.

Why C is correct:

• Transition metals like palladium show multiple oxidation states (e.g., +2, +4) per IUPAC definition, and compounds like PdCl2 act as catalysts in processes like hydrogenation.

Why the others are wrong:

• A: Palladium's density (12 g/cm³) far exceeds sodium's (0.97 g/cm³); not all compounds are white.
• B: Density mismatch with sodium; catalytic property alone incomplete without oxidation states.
• D: Multiple oxidation states correct, but many palladium compounds (e.g., PdO black) are not white.

Final answer: C