1. The problem statement, all variables and given/known data Show that the bond length for sodium chloride is 0.28nm given that it has a relative density of 2.2, sodium has an atomic weight of 23, and chlorine 35.5. Avogadro's number is 6.0x10^23 2. Relevant equations 3. The attempt at a solution I've tried many things but here's one: molar mass of NaCl = 23 + 35.5 = 58.5g. Relative density = 2.2g/cm^3. Therefore 58.5g= 26.59cm^3 of NaCl. One side = cube root of 26.59 = 2.98cm = 42171633 = 7.066x 10^-8cm per molecule. So divide through by 2 again to find bond length = 0.35nm. which isn't 0.28nm.