14. (5 points) Calculate the ionic packing factor (IPF) of MgO, which has the NaCl structure. (rMg2+=0.066nm; rO2-=0.132nm)?
A) 0.157 B) 0.597 C) 0.698 D) 0.941
15. Using the information in question 14, calculate the density of MgO in g/cm^3. Data: the atomic weights of Mg and O are 24.31 and 16 g/mol respectively.
A) 2.22 B) 1.80 C) 4.31 D) 14.31
16. (5 points) Suppose that four Schottky defects are present in ten unit cells of MgO from questions 14 and 15. Calculate the density of the ceramic in g/cm^3.
A) 4.31 B) 3.88 C) 2.10 D) 14.20