Which statement best compares the melting points of magnesium and sodium?

• A. Sodium has a higher melting point than magnesium because it has more valence electrons.
• B. Magnesium and sodium have similar melting points because they are both metals.
• C. Magnesium has a higher melting point than sodium because it has stronger metallic bonding.
• D. Sodium has a higher melting point than magnesium because it is more reactive.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand that melting point in metals is largely influenced by the strength of metallic bonding, which depends on the number of delocalized valence electrons and the charge of the metal cations.
2. Step 2: Recognize that magnesium (Mg) has two valence electrons and forms Mg²⁺ ions, while sodium (Na) has one valence electron and forms Na⁺ ions.
3. Step 3: Since magnesium ions have a higher positive charge and contribute more valence electrons to the 'sea of electrons,' the metallic bonding in magnesium is stronger than in sodium.
4. Step 4: Stronger metallic bonding requires more energy to break, resulting in a higher melting point for magnesium compared to sodium.
5. Step 5: Therefore, the statement that magnesium has a higher melting point than sodium because it has stronger metallic bonding best explains the difference in their melting points.