= Solution
Metallic atomic densities place very many <electrons> in a small volume. The <Pauli exclusion principle> prevents all these <fermions> occupying the lowest spatial state, so filling the available states produces a <Fermi energy> of order electronvolts. At room <temperature>, $k_{\rm B}T\simeq0.026\ {\rm eV}$, much smaller than that scale. Equivalently, \b[ordinary metals are at $T\ll T_F=E_F/k_{\rm B}$], where $T_F$ is the <Fermi temperature>. Their <electrons> are quantum degenerate even at ordinary laboratory temperatures.
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