Two plausible Lewis structures for the nitrite ion, NO₂⁻
CHEMISTRY · Single correct · A Level · Chemistry · Bonding · Bonding
Problem
Two plausible Lewis structures for the nitrite ion, NO₂⁻, are described below.
• Structure 1: N is double-bonded to one O and single-bonded to the other O; only the singly bonded O bears a formal charge of –1.
• Structure 2: N is single-bonded to both O atoms; each O bears a formal charge of –1.
Which statement best explains why Structure 1 is the better representation of NO₂⁻?
(a) Structure 1 is preferred because it places the negative formal charge on an oxygen atom, which is more electronegative than nitrogen.
(b) Structure 1 is preferred because nitrogen can expand its valence shell beyond an octet, reducing electron-pair repulsion.
(c) Structure 1 is preferred because it minimizes the total number of atoms that carry a non-zero formal charge.
(d) Structure 1 is preferred because the two N–O single bonds it predicts are shorter than an N=O double bond, matching experimental data.