Here's how to calculate the number of atoms in 1.3 x 10^22 molecules of NO2:

1. Understand the Formula:

* NO2 represents one molecule of nitrogen dioxide.

* Each molecule contains 1 nitrogen atom (N) and 2 oxygen atoms (O).

2. Calculate the Total Number of Atoms per Molecule:

* 1 nitrogen atom + 2 oxygen atoms = 3 atoms per NO2 molecule

3. Multiply by the Number of Molecules:

* (1.3 x 10^22 molecules of NO2) * (3 atoms/molecule) = 3.9 x 10^22 atoms

Therefore, there are 3.9 x 10^22 atoms in 1.3 x 10^22 molecules of NO2.