Which ion listed below has exactly three equivalent resonance structures?

CHEMISTRY · Single correct · A Level · Chemistry · Bonding · Bonding

Problem

Which ion listed below has exactly three equivalent resonance structures? (a)

\text{NO}_2^-

(b)

\text{NO}_3^-

(c)

\text{ClO}_4^-

(d)

\text{SO}_4^{2-}