Thermal conductivity, 286 Virtual state

Classical Free-Electron Theory, Classical free-electron theory assumes the valence electrons to be virtually free everywhere in the metal. The periodic lattice field of the positively charged ions is evened out into a uniform potential inside the metal. The major assumptions of this model are that (1) an electron can pass from one atom to another, and (2) in the absence of an electric field, electrons move randomly in all directions and their movements obey the laws of classical mechanics and the kinetic theory of gases. In an electric field, electrons drift toward the positive direction of the field, producing an electric current in the metal. The two main successes of classical free-electron theory are that (1) it provides an explanation of the high electronic and thermal conductivities of metals in terms of the ease with which the free electrons could move, and (2) it provides an explanation of the Wiedemann-Franz law, which states that at a given temperature T, the ratio of the electrical (cr) to the thermal (k) conductivities should be the same for all metals, in near agreement with experiment ... 

The liquid state of matter is intermediate in its physical properties between the solid and gaseous states. Chemists who study reactions in solution deal with the so-called normal liquids, very rarely they deal with liquid crystals, and do not virtually work with quantum liquids. In the absence of external actions, normal liquids are macroscopically uniform and isotropic. A liquid is close to a solid in many properties, especially near the melting point. As a solid, a liquid has the interface and withstands strong tensile forces without rupture. The liquid and solid have close values of density, specific thermal capacity, specific thermal conductivity, and electric conductivity. All this is a result of tight contact between molecules in the liquid and solid. 

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