In a metal, each atom and its core electrons are connected by "springs" to each of their neighbors. This would give a specific heat capacity of Cv= 3 KB. In addiction, each atom donates an electron to the conduction bound where they behave like a gas of electron. Explain qualitatively therefore why the head capacity of the metal is not 3 KB + 3/2 KB and is instead very close to 3 KB for most temperatures of interest.