Density of copper is 8.92×10^3 kgm-3mass of 1 mole of copper is 6.35×10^-2kg
copper adopts a face-centered cubic arrangement in its crystal lattice. What this means is that the diagonal from one corner of a phase of the unit cell to the opposite corner of the same phase is equivalent to 4r and also equals (2^1/2)a; therefore, r = [(2^1/2)/4]a = a/(2(2^1/2)) Since the edge of the unit cell equals a, the separation between two copper atoms on the edge of the unit cell is: Hole = a - 2a/(2(2^1/2) = a[1 - (2^1/2)/2] = 0.293a I hope that answers your question.
