An $fcc$ unit cell of aluminium contains the equivalent of how many atoms?

The ratio of anion radius to cation radius of a crystal is $10 : 9.3$. Then, the coordination number of the cation in the crystal is

The crystal structure of $AB$ is of $NaCl$ type. If the radius of the $A^+$ ion is $x \ pm$ and the radius of the $B^-$ ion is $y \ pm$, then the edge length of the unit cell will be ..........

An alloy made up of $A$ and $B$ metals crystallises in a cubic lattice, where $B$ atoms occupy the corners and $A$ atoms occupy the face centers. The formula of the alloy formed is

Potassium fluoride $(KF)$ has a $NaCl$ type structure. If the edge length of the unit cell is $a$,what is the distance between $K^+$ and $F^-$ ions?

The arrangement of $X^{-}$ ions around $A^{+}$ ion in solid $AX$ is given in the figure. If the radius of $X^{-}$ is $250 \ pm$, the radius of $A^{+}$ is: (in $pm$)