a) if the ionic radil are 0.076 nm, and 0.126 nm for Fe and consider the cubic unit cell shown to the right for Feo ions, respectively, which crystal structure does Feo exhibit. [1 point) (Hint: choose from NaCl, CsCI, Zns or CaFa). Iron(I1) oxide b) Calculate the theoretical density of FeO. [2 points] Fe