Crystalline sodium (Na) is a metal. One can consider that each and every atom contributes to the density of free electrons having the number of electrons at the higher energy atomic orbital (s-band in this case). Beneath this supposition, compute for Na:
(i) The density of free electrons.
(ii) The value of the Fermi level.
(iii) When the relaxation time is ~2.6 x 10-14 s, compute the electrical conductivity.