Question 1
Multiple choiceMedium1 markIn the metallic model, sodium forms Na⁺ ions and magnesium forms Mg²⁺ ions; Mg²⁺ has a smaller radius than Na⁺. Which row predicts the metal with stronger metallic bonding and the metal with the higher melting point, respectively?
Show answer and explanation
Answer: C. Mg²⁺ has a greater charge and smaller radius than Na⁺, so it attracts delocalized electrons more strongly. Stronger metallic bonding requires more energy to overcome during melting, so Mg has the higher melting point.
A: treats the larger radius of Na⁺ as strengthening the attraction and carries that reversal through to melting point.
B: identifies Mg as more strongly bonded but reverses the relationship between bonding strength and melting point.
D: assigns the higher melting point to Mg but incorrectly assigns stronger metallic bonding to Na.
Remember: greater cation charge and smaller radius strengthen metallic bonding; stronger bonding generally corresponds to a higher melting point.