Exam Style Questions

Calcium has a metallic lattice and metallic bonding. Methane has a simple molecular structure and inter molecular forces between molecules. Metallic bonding in calcium is stronger that inter molecular forces in methane. Thus more energy is needed to overcome metallic bonding in calcium.

In terms of structure and bonding , explain why Calcium has a higher Boiling point than Methane?

In terms of structure and bonding explain why Sodium Oxide has a higher melting point than phosphorus pent-oxide (P4O10)

Sodium oxide has ionic bonding with ionic lattice. Phosphorus pent-oxide is simple molecular with inter molecular forces between molecules. Ionic bonding in sodium oxide is stronger than inter molecular forces in Phosphorus pent-oxide. More energy is required to overcome the ionic bonds in sodium oxide.

Explain why aluminium has a higher melting point than sodium.

Aluminium and sodium are both metallically bonded with metallic lattice. Aluminium has more protons and a higher charge but smaller radius. So aluminium attracts delocalised electrons more strongly, forming stronger bonds.