Silicon has a face-centered cubic crystal structure with unit cell edge length of 5.43 Angstrom and four atoms per unit cell.
Part A : How many silicon atoms are there in 1 cm^3 of material?
Part B: Suppose you dope that 1-cm^3 sample of silicon with 1 ppm of phosphorus that will increase the conductivity by a factor of a million. How many milligrams of phosphorus are required?