The number of atoms in 1.75 ml of mercury is 7.1036 x10^22 atoms
calculation
find mass of Hg= M xV
=1.75 ml x 13.5 g/ml =23.625 grams
find the number of moles of Hg =mass/molar mass
moles= 23.625g/200.56g/mol=0.118 moles
by use of Avogadro law that is 1 mole= 6.02 x10^23 atoms
0.118 moles=? atoms
by cross multiplication
=(0.118 moles x6.02 x10^23atoms) /1 mole= 7.091 x10^22 atoms