Question

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

• A. 421
• B. 334
• C. 481
• D. 193

Answer 1

Answer: (B)

Given,
density of polonium $=9.32gc{m}^{-3}$
As we know, $\rho =\frac{M\times Z}{V\times N_A}$
where, $\rho =$ Density
$M=$ Mass of the element
$Z=$ Number of atom in a unit lattice
$V=$ Volume
$N_A=$ Avogadro's number
For scc, $Z=1$
$\therefore 9.32=\frac{209\times 1}{a^3\times 6.022\times 10^{23}}$
$a^3=37.2\times 10^{-24}$
$a=3.33\times 10^{-8}cm\approx 334pm$