The density of solid fe is 7.87 g/cm3. how many atoms are present per cubic centimeter of fe?

The average that reflect the typical ratio of natural abundance of iron isotope is the atomic weight of the iron. Iron has four stable isotope that is iron 54,56, 57, 58. its atomic weight by mass is 9.27 x10^-22 grams

therefore number of atoms in cm^3 is

(7.87g/cm^3) / (9.27x10^-22) = 8.49x10^21atoms/cm^3