$A$ metal crystallizes in a simple cubic lattice. The volume of one unit cell is $6.4 \times 10^7 \ pm^3$. What is the radius of the metal atom in $pm$?

Silver forms a $CCP$ structure and its density is $10.5 \ g/cm^3$. What is the edge length of the unit cell? (Molar mass of silver is $107.9 \ g/mol$)

Calculate the number of unit cells in $1 \ cm^3$ volume of metal if the unit cell edge length is $1.25 \times 10^{-8} \ cm$.

Polonium (atomic mass = $209$) crystallises in a simple cubic structure with a density of $9.32 \ g \ cm^{-3}$. Its lattice parameter (in $pm$) is closest to:

Select the $INCORRECT$ option regarding the cubic crystal system-

Sodium metal crystallises in a body-centred cubic $(BCC)$ lattice with an edge length of $x \ \mathring{A}$. If the radius of the sodium atom is $1.86 \ \mathring{A}$, the value of $x$ is: