Exam Style Questions

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

• 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 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.