Au is FCC cell. Given that molecular mass of Au is 197, avogadro number is 6.02*10^23 and length of edge is 0.41nm
My solutions :
Find radius, density, one atom surrounded by how many nearest neighbour atom
Finding radius : 4r = a*root(2) ; a = edge
r = (0.41 * root(2))/4 = 0.1449 = 0.15 (2 significant figures)
Finding density : D = (4 * 197 * 1/6.02*10^23) / (0.41*10^-7)^3 = 19 (2 significan figures)
but I don't know how to find number of nearest neighbour atoms.