The atomic mass of platinum is 195.1. A cube of platinum weighs 24.8g and its density is 21.45g/cm^3.

Calculate.

If we consider the sample is composed of spherical atom each with radius r and volume Vatom =4/3Pir^3, and if we assume that the total volume of the spheres in the sample is 74% of the total volume, calculate the radius of a single platinum atom in picometers.