Metallic Bonding Model

Steps:

• Recall the metallic bonding model: positive metal ions in a lattice surrounded by delocalized valence electrons.
• Evaluate A: Incorrectly describes ions as negative; metal ions are positive cations.
• Evaluate B: Matches the model, as delocalized electrons move freely throughout the lattice.
• Evaluate C: Malleability arises from electron sea allowing ion layers to slide, not ion mobility alone.
• Select B as it accurately describes electron behavior in metals.

Why B is correct:

• In metallic bonding, valence electrons are delocalized, moving randomly through the ion lattice, enabling electrical conductivity per the "sea of electrons" model.

Why the others are wrong:

• A: Metal ions are positive (cations), not negative; electrons form the surrounding sea.
• C: Malleability results from delocalized electrons allowing ion planes to shift without breaking bonds, not mobile ions.
• D: Ions remain fixed in the lattice; only electrons move under an electric field.

Final answer: B