If $TlCl$ crystallizes in a $bcc$ structure,then the sum of the radii of the cation and anion will be ........ ($a =$ edge length).

Calculate the edge length of a simple cubic unit cell if the radius of an atom is $167.3 \ pm$. (in $pm$)

Ammonium chloride crystallizes in a body-centered cubic lattice with an edge length of the unit cell of $390 \ pm$. If the size of the chloride ion is $180 \ pm$,the size of the ammonium ion would be ........... $pm$.

An element (atomic mass $= 60$) has a face-centered cubic $(FCC)$ structure with a density of $6.23 \ g \ cm^{-3}$. The edge length of the unit cell is.... $(N_A = 6.02 \times 10^{23} \ mol^{-1})$

An element with atomic mass $100$ has a $bcc$ structure and edge length $400 \, pm$. The density of the element is .............. $g \, cm^{-3}$.

$A$ compound can crystallise in two forms $\alpha$ and $\beta$ which are $fcc$ and $bcc$, respectively. The $\alpha$-form has a side length of $2 \ pm$ and the $\beta$-form has a side length of $4 \ pm$. The ratio of their density $\frac{\rho_\alpha}{\rho_\beta}$ is