Metallic Character and Valence Electrons in Period 5

Steps:

• Identify positions: Indium (Z=49) in Group 13 (III), Period 5; antimony (Z=51) in Group 15 (V), Period 5.
• Compare metallic character: Decreases across a period from left to right; indium (left) is a metal, antimony (right) is a metalloid.
• Compare valence electrons: Group number equals valence electrons for p-block; indium has 3 (ns²np¹), antimony has 5 (ns²np³).
• Match to options: Indium has more metallic character, antimony has more valence electrons.

Why B is correct:

• Aligns with periodic trends: Metallic character increases leftward; valence electrons match group numbers in main groups.

Why the others are wrong:

• A: Wrong on metallic character (antimony less metallic) and valence electrons (indium has fewer).
• C: Wrong on valence electrons (indium has 3, not more than antimony's 5).
• D: Wrong on both (indium more metallic, fewer valence electrons).

Final answer: B