Solution:
Solution
SInce Si has diamond cubic structure, its unit cell contains $$8$$ atoms.
Density $$\displaystyle = \dfrac {\text{Mass}}{\text{Volume}} $$
Mass $$\displaystyle = 8 \times 28.08 \times 1.66 \times 10^{-27} = 3.73 \times 10^{-25} $$ kg
Volume $$\displaystyle = (5.43 \times 10^{-10})^3 = 1.6 \times 10^{-28} \: $$ m$$^3$$
Density $$\displaystyle = \frac {3.73 \times 10^{-25} }{ 1.6 \times 10^{-28}} = 2330$$ kg m$$^{-3}$$
