Aluminum oxide's bonding and amphoteric properties

Steps:

• Aluminum, a metal, bonds ionically with oxygen, a non-metal, due to large electronegativity difference.
• This forms a giant ionic lattice structure with high melting point.
• Aluminum oxide reacts with acids (e.g., HCl) to form salts and with bases (e.g., NaOH) to form aluminates.
• Thus, it is giant ionic and amphoteric.

Why C is correct:

• Aluminum oxide (Al₂O₃) has a giant ionic lattice and is amphoteric, as defined by its ability to act as both acid and base per Arrhenius and Lewis theories.

Why the others are wrong:

• A: Bonding is giant ionic, not simple covalent like water.
• B: Structure is giant ionic, not covalent like silicon dioxide; also amphoteric, not basic only.
• D: Amphoteric, not basic only like calcium oxide.

Final answer: C