Understanding Thermal Conductivity in Metals

Thermal conductivity is a property of a material that indicates how well it conducts heat. Materials with high thermal conductivity allow heat to pass through them quickly, while materials with low thermal conductivity are poor heat conductors (insulators). The question asks to identify the metal having the lowest thermal conductivity among the given options.

Let's examine the thermal conductivity of the metals listed:

• Copper: Copper is a well-known metal with high electrical and thermal conductivity, often used in wiring and heat sinks.
• Mercury: Mercury is a unique metal as it is a liquid at room temperature. Its properties, including thermal conductivity, are different from solid metals.
• Aluminium: Aluminium is another metal widely used due to its good thermal conductivity and low density.
• Silver: Silver is generally considered to have the highest thermal conductivity among all metals.

Comparing Thermal Conductivity Values

To find the metal with the lowest thermal conductivity, we need to compare their typical thermal conductivity values. These values are usually measured in Watts per meter-Kelvin (\( W/(m \cdot K) \)).

Comparing the values from the table:

• Silver has the highest value, followed closely by Copper.
• Aluminium has a significantly lower value than Silver and Copper, but is still a good conductor.
• Mercury has a thermal conductivity value of approximately \( 8.3 \, W/(m \cdot K) \), which is considerably lower than the values for Silver, Copper, and Aluminium.

Therefore, based on the typical thermal conductivity values, Mercury is the metal that has the lowest thermal conductivity among the given options.

Revision Table: Metal Thermal Conductivity

Additional Information: Why Metals Conduct Heat

Metals are generally good thermal conductors primarily because of the presence of free electrons in their structure. These free electrons can move throughout the metal lattice and efficiently transfer kinetic energy, which is essentially heat. Heat can also be transferred by vibrations of the atoms in the lattice (phonons), but in metals, electron transport is usually the dominant mechanism for thermal conduction.

The unique liquid state of Mercury at room temperature means its atomic structure and electron movement are different from solid metals, resulting in a lower thermal conductivity compared to common solid metals like Silver, Copper, and Aluminium.