Question

How many atoms are in 1.4 mol of phosphorus trifluoride (PF3)?

Answer 1

Number of atoms in 1.4 mol of Phosphorus trifluoride (PF₃) : 8.428 x 10²³

Further explanation  

The mole is the number of particles(molecules, atoms, ions) contained in a substance  

1 mol = 6.02.10²³ particles

Can be formulated

N=n x No

N = number of particles

n = mol

No = Avogadro's = 6.02.10²³

1.4 mol of Phosphorus trifluoride (PF₃), number of atoms :

$\tt N=1.4\times 6.02\times 10^{23}\\\\N=8.428\times 10^{23}$