Identify the non-metal, having high thermal conductivity.

Concept:

Non-metal:

• Non-metals are the elements that form negative ions by accepting or gaining electrons.
• Non-metals usually have 4, 5, 6 or 7 electrons in their outermost shell.
• Non-metals are those which lack all the metallic attributes. They are good insulators of heat and electricity.
• They are mostly gases and sometimes liquid.
• Some of then are even solid at room temperatures like Carbon, sulphur and phosphorus.

Thermal Conductivity:

• Thermal conductivity refers to the ability of a given material to conduct/transfer heat.
• It is generally denoted by the symbol ‘k’ but can also be denoted by ‘λ’ and ‘κ’.
• The reciprocal of this quantity is known as thermal resistivity.
• Materials with high thermal conductivity are used in heat sinks whereas materials with low values of λ are used as thermal insulators.
• The law of heat conduction states that the rate at which heat is transferred through a material is proportional to the negative of the temperature gradient and is also proportional to the area through which the heat flows.
• The differential form of this law can be expressed through the following equation: q = - k ΔT, where k = thermal conductivity,  ΔT = temperature gradient,  q = heat flux

Explanation:

• The thermal conductivity of wood is generally within the range of 0.1–0.2 W/mK.
• The thermal conductivity of water is 0.598 W/m·K at 20°C.
• The thermal conductivities of the ice samples prepared by the 0% CAS and 50% CAS air-blast freezing methods measured at −29°C are both 2.75 ± 0.03 W/(m·K).
• Bricks possess a low thermal conductivity which averages between 0.5 – 1.0 W/(m/K). 
• Hence, the ice has a higher thermal conductivity.