Answer
2.06x 10²⁴ atoms
Procedure
To calculate the atoms in a molecule we will need to multiply the moles by Avogadro's number 6.0221408 x 10²³.
[tex]3.42\text{ mol AgNO}_3\frac{6.0221408\times10^{23}\text{ atoms AgNO}_3}{1\text{ mol AgNO}_3}=2.0596\times10^{24}\text{ atoms AgNO}_3[/tex]