Packing in Solids — Prelims Questions

An element crystallizes in a face-centered cubic (FCC) lattice. If the atomic radius of the element is $125,\text{pm}$, what is the edge length of the unit cell?

A compound is formed by elements A and B. Atoms of element B form a cubic close-packed (CCP) lattice, and atoms of element A occupy $\frac{2}{3}$ of the tetrahedral voids. What is the formula of the compound?

Which of the following statements about packing efficiency is correct?

What is the coordination number of an atom in a body-centered cubic (BCC) lattice?

If the radius of the constituent particles in a simple cubic unit cell is 'r', what is the relationship between 'r' and the edge length 'a' of the unit cell?

In a close-packed structure, if the number of constituent particles is N, what is the ratio of tetrahedral voids to octahedral voids?