The atomic radius of stronitum is $215\;pm$ and it crystallizes with a cubical closest - packed structure . Calculate the density of strontium. The molar mass of strontium is $ 87.6\;g\;mol^{-1}$

Question

$\begin{array}{1 1} 2.586\;g\;cm^{-3} \\ 7 .34\;g\;cm^{-3} \\ 8\;g\;cm^{-3} \\ 9\;g\;cm^{-3} \end{array} $