Question 8.8: The widespread use of fertilizers has resulted in the contam...
The widespread use of fertilizers has resulted in the contamination of some groundwater with nitrates, which are potentially harmful. Nitrate toxicity is due primarily to its conversion in the body to nitrite (NO_{2}^{-} ), which interferes with the ability of hemoglobin to transport oxygen. Determine the formal charges on each atom in the nitrate ion (NO_{3}^{-} ).
Strategy Use steps 1 through 6 on page 314 for drawing Lewis stuctures to draw the Lewis structure of NO_{3}^{-} . For each atom, subtract the associated electrons from the valence electrons.
Setup
The N atom has five valence electrons and four associated electrons (one from each single bond and two from the double bond). Each singly bonded O atom has six valence electrons and seven associated electrons (six in three lone pairs and one from the single bond). The doubly bonded O atom has six valence electrons and six associated electrons (four in two lone pairs and two from the double bond).
The formal charges are as follows: +1 (N atom), -1 (singly bonded O atoms), and 0 (doubly bonded O atom).