Question

the thing that is troubling me is that NO2 is not (NO2)-

does that change it from being considered a lewis base to a lewis acid?

Answer 1

I don't think that NO2 would be likely to accept a "single electron" but I don't know that. If we change it to a nitrite ion (NO2^-), then we can draw a legitimate Lewis electron dot structure. The one I drew for myself (since we can't do these on the boards) is O-N=O with six electrons around the left O, four more electrons around the right O which gives the right O an octet, the left O and octet, and N an octet with a -1 formal charge on the left O. But with an octet for N, there is no reason for adding electrons to it; i.e., an octet is sufficient AND more electrons than an octet can't be accommodated by N. So I don't see NO2 or NO2^- being a Lewis acid but organic puzzles me anyway.