Why aluminium oxide has high melting point?
Unfortunately those are both wrong. Aluminium Oxide (Al2O3) is an ionic compound [with some covalent character]. For a GCSE answer you need to say: 1. It is made of Al(3+) and O(2-) ions. 2. These form a giant lattice. 3. Ionic bonds are very strong intermolecular forces. 4. These ionic bonds must be broken to melt the compound. For an ‘A’-level anser you would need to describe more. But this is more than enough for GCSE.
