Non-malleable electron conductor in atomic lattice

Steps:

• Define malleability as the ability to deform into thin sheets without breaking, common in metals with delocalized electrons.
• Identify electrical conduction via electron movement through an atomic lattice as a property of metallic bonding or graphite's layered structure.
• Eliminate options that are malleable (metals) or conduct via ions rather than electrons.
• Select the substance that conducts electrons but lacks malleability due to its brittle, layered form.

Why C is correct:

• Graphite conducts electricity through delocalized π electrons in its hexagonal carbon lattice but is not malleable because its weak interlayer forces cause it to cleave rather than deform.

Why the others are wrong:

• A: Aqueous sodium chloride conducts via mobile ions in solution, not electrons through a lattice.
• B: Gold is highly malleable due to its metallic bonding allowing easy layer sliding.
• D: Solid sodium chloride is an ionic insulator that does not conduct electricity and is brittle, not malleable.

Final answer: C