Answer:

Step-by-step explanation:
According to avogadro's law, 1 mole of every substance occupies 22.4 L at STP and contains avogadro's number
of particles.
1 mole of
contains =
atoms of mercury
Thus 4.5 moles of
contains =
atoms of mercury
Thus the number of atoms in 4.5 moles of mercury are
atoms of mercury.