Packing Efficiency — Prelims Questions

An element crystallizes in a body-centered cubic (BCC) structure. If the atomic radius of the element is $173.2,\text{pm}$, what is the edge length of the unit cell?

What is the percentage of void space in a face-centered cubic (FCC) unit cell?

Which of the following cubic unit cells has the lowest packing efficiency?

An element with atomic mass $M$ crystallizes in an FCC lattice with unit cell edge length 'a'. What is the expression for its density?

If the packing efficiency of a crystal structure is $68\%$, what type of cubic unit cell does it most likely represent?

In a face-centered cubic (FCC) unit cell, what is the relationship between the edge length 'a' and the atomic radius 'r'?