Concept:Metallic bonding strength depends on the number of delocalized electrons available to attract positive metal ions.
Explanation:Aluminium atoms release their outermost electrons, which move freely throughout the metal structure.
These free-moving electrons are called delocalized electrons.
They form a “sea of electrons” that surrounds the fixed, positively charged aluminium ions.
Aluminium contributes three delocalized electrons per atom, which is a large number.
This large electron sea creates a very strong electrostatic attraction between the electrons and the metal ions.
Therefore, aluminium has strong metallic bonding because of the large number of delocalized electrons.
Answer:A. delocalized electrons