What is the length of the body diagonal in a $bcc$ structure?

Calculate the molar mass of an element having density $7.8 \ g \ cm^{-3}$ that forms a $bcc$ unit cell. $\left[a^3 \cdot N_{A} = 16.2 \ cm^3 \ mol^{-1}\right]$

An element crystallizes in an $fcc$ unit cell structure with an edge length of $200 \, pm$. If $200 \, g$ of the element contains $24 \times 10^{23}$ atoms, what is its density in $g/cm^3$?

An element has a $BCC$ structure. The edge length of the unit cell is $288 \, pm$. If the density of the crystal is $7.2 \, g \, cm^{-3}$, what is the atomic mass of the element?

If the edge length of a unit cell of $Li$ is $351 \, pm$, what is the radius of $Li$ (in $pm$)?

In an ionic compound with a $bcc$ structure, the distance between the two nearest ions is $173 \, pm$. What is the edge length of the unit cell in $pm$?