Question

How do magnesium and sodium form a bond? Explain​

Answer 1

Answer:

The metal atoms become positive ions and the non-metal atoms become negative ions. There is a strong electrostatic force of attraction between these oppositely charged ions – this is called an ionic bond. The slideshow shows ionic bonds being formed in sodium chloride, magnesium oxide and calcium chloride.

If you work through the same argument above for sodium with magnesium, you end up with stronger bonds and hence a higher melting point. Magnesium has the outer electronic structure 3s2. Both of these electrons become delocalized, so the "sea" has twice the electron density as it does in sodium.

Hope it helps