Which element is likely to have the highest thermal conductivity?
antimony
carbon
sodium
gallium

Answer is: sodium.

Thermal conductivity is the property of a material to conduct heat.

In the International System of Units (SI), thermal conductivity is measured in watts per meter-kelvin (W/(m⋅K)).

Metallic bond increace electrical and thermal conductivity.

Thermal conductivity of sodium is 140 W/(m·K).

Thermal conductivity of antimony is 24 W/(m·K).

Thermal conductivity of gallium is 40 W/(m·K).

6.4 cm (max) - 25 cm (min)

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.