Current Attempt in Progress

A certain monovalent metal has density $12\mathrm{.}21\frac{g}{c}{m}^3$ and molar mass $91\mathrm{.}0\frac{g}{m}ol.$ Calculate $($a$)$ the number density of conduction electrons, $($b$)$ the Fermi energy, $($c$)$ the Fermi speed, and $($d$)$ the de Broglie wavelength corresponding to this electron speed.