Determine the number of atoms contained in 4.2 moles of atomic bromine.

Answer :

Avogadro's number

1 mole = 6.02.10²³ particles (atoms, molecules, ions)

for 4.2 moles:

[tex]\tt 4.2\times 6.02\times 10^{23}=\boxed{\bold{2.53\times 10^{24}atoms}}[/tex]