## Chemistry: The Molecular Science (5th Edition)

$NO_2$ and $NO_3$
To find the number of valence electrons, multiply the number of valence electrons of each element by the number of that element in the molecule. Recall, Oxygen has 6 valence electrons, and Nitrogen has 5 valence electrons. In addition, Hydrogen has one valence electron, Sulfur has 6, and Chlorine has 7. Using this information, we find that $NO_2$ and $NO_3$ are the only ones with an odd number of valence electrons.