Answer
$6.78\times10^{21}\ atoms\ Hg$
Work Step by Step
1.Use the molar mass of mercury and Avogadro's number as conversion factors in order to determine the number of atoms of mercury.
2. $2.26 g\ Hg \times\frac{1\ mol\ P}{230.29\ g\ P}\times\frac{6.022\times10^{23}}{1\ mol\ P}= 6.78\times10^{21}\ atoms\ Hg $
