Why are metals able to conduct electricity in solid form?

• A. They form ionic bonds in the solid.
• B. Because of delocalised electrons in a lattice or 'sea of electrons' that move and carry charge.
• C. They have high density.
• D. They are arranged in a lattice of cations.

Answer: (B)

The main idea is that metals conduct electricity in the solid state because of delocalised electrons that move freely through the structure. In a metal, outer electrons aren’t tied to any one atom; they form a “sea” of electrons around a fixed lattice of positive metal ions. When you apply a voltage, these electrons drift and carry charge through the metal, allowing electrical current to flow.

If bonds were ionic in the solid, ions would be locked in place and there would be no mobile charge carriers to move and carry the current. A high density or a lattice of cations alone doesn’t provide free-moving charge; without those delocalised electrons, conductivity wouldn’t occur.