Explain thermal conductivity & give its variation in case of solid, liquids and gases?

Conduction is the transfer of energy from the more energetic particles of a substance to the adjacent less energetic ones as a result of interactions between the particles. Conduction can take place in solids, liquids, or gases. In gases and liquids conduction is due to the collisions and diffusion of the molecules during their random motion. In solids conduction is due to the combination of vibrations of the molecules in a lattice and the energy transport by free electrons.