Physical and chemical properties

Metals have free electrons. These electrons move easily to carry electric charge and also help transfer heat energy. Therefore, metals are generally good conductors of both heat and electricity. Options B and C are incomplete because metals generally show both types of conductivity. Exam tip: Copper and aluminium are common examples of conducting metals.

Silver is the best electrical conductor because it has very low electrical resistance and its free electrons move easily. Copper is also an excellent conductor and is used more often in wires because it is cheaper, but its conductivity is lower than that of silver. Exam tip: Remember that silver ranks above copper in electrical conductivity.

The property by which a metal can be drawn into thin wires without breaking is called ductility. Copper and aluminium are ductile metals, so they are commonly used for electrical wires. Malleability refers to forming thin sheets by hammering, not drawing wires. Exam tip: associate wires with ductility and sheets with malleability.

The ability of a metal to be hammered into thin sheets without breaking is called malleability. Ductility is the ability to be drawn into wires, so it is a close but incorrect option. Exam tip: remember—sheets indicate malleability, while wires indicate ductility.

Mercury is liquid at room temperature because its melting point is about
ext{−39}^
ext{°C}, which is below normal room temperature. Iron, copper and aluminium have much higher melting points, so they remain solid at room temperature. Exam tip: Remember mercury as the metal that is liquid at room temperature.