1 molecule of NO2 included N atom and 2 oxygen atoms, so a total of 3 atoms per molecule.
1.3 x 10^22 times 3 = 3.9 x 10^22 atoms
Answer is: <span>D. Tin atoms give electrons to lead(II) ions and are oxidized to tin(II) ions.
Chemical reaction: Sn</span>⁰ + Pb²⁺ → Sn²⁺ + Pb.
Tin atom (oxidation number 0) give two electrons to led ions, oxidation number of tin is greater now (oxidation number +2).
<span>Oxidation is loss of electrons.</span>
i think that the answer is D