## Chemistry and Chemical Reactivity (9th Edition)

Only $NH_3$: nitrogen has 5 valence electrons, and it's making 3 bonds $NO_2$ and $ClO_2$ are radicals (odd number of valence electrons), in $SF_4$, and $ClO_2^-$ the central atom is hypervalent. Contrarily, we know that $SO_3$, like $NH_3$, follows the octet rule through resonance.