Metallic Bonding in Element X

Steps:

• Identify the description "lattice of positive ions and a sea of electrons" as metallic bonding, characteristic of metals.
• Recall that metallic bonds involve strong electrostatic attractions between cations and delocalized electrons.
• List key metal properties: high melting points, electrical conductivity via electrons, malleability, and stability under current.
• Match properties to options, selecting the one directly tied to bond strength.

Why B is correct:

• Metallic bonds form a strong lattice requiring high energy to overcome, leading to high melting points as per the definition of metallic bonding.

Why the others are wrong:

• A: Metals conduct via mobile electrons only; ions remain fixed in the lattice.
• C: Metals are not decomposed by electric current; this applies to electrolytes in electrolysis.
• D: Metals are malleable due to layers of ions sliding past each other.

Final answer: B