[galpinj]

So I have been doing some practice problems with Lewis structures, and I had a bit of an issues with HNO₃

I was fiddling around and am curious why it would be wrong to have an oxygen-oxygen bond (H-NO₂-O). If you write it out you'll find that one oxygen has a FC of -1 and the N has a FC of +1 (much like the real structure, pictured below).

I'm thinking that maybe the ability for the pictured structure to form resonance structures makes it more stable/the better choice, but I'm not certain. Is there something going on that I'm missing here?

[AWK]

Very nice idea. It is as good as this one presented for the first time in 1865 by Prof. A. W.Hofmann, On the Combining Power of Atoms,
Notices of the Proceedings at the Meetings of the Members of the Royal Institution, with Abstracts of the Discourses 4 (1865) 401-430
But this happened 151 years ago.
 

[Babcock_Hall]

It seems to me that the proposed structure is unrealistic.  Why would nitric acid be a strong acid if the proton that will dissociate is bound to a nitrogen?  Also, if this were the structure, there should be a large N-H coupling constant.

[galpinj]

Very nice idea. It is as good as this one presented for the first time in 1865 by Prof. A. W.Hofmann, On the Combining Power of Atoms,
Notices of the Proceedings at the Meetings of the Members of the Royal Institution, with Abstracts of the Discourses 4 (1865) 401-430
But this happened 151 years ago.

That really made me laugh. I always feel like I'm not the brightest light in the house when talking with the many intelligent people in this forum; good to know I'd do okay if it was the 19th century!

I agree with you Babcock, it doesn't really seem realistic. I was just wondering if there was some rule it was breaking, because the formal charges seem to balance nicely.

[AWK]

Not exactly! Your structure contains two coordination bonds: H-N(=O)->O->O which (both) should be rather weak. Oxygen coordinated to metal forms extremely week complex (eg. hemoglobin). But oxygen donates electron pair. And we know that nitric acid is quite stable. Moreover, as Babcock_Hall pointed out, acidic proton in acids containing oxygen is always attached to oxygen. Even Prof. Hofmann in 1865 knew that. In these times for chlorine in all compounds valency 1 was ascribed so such models for presentation he prepared from croquet balls. Some of them still exist! Flat methane model is the most popular.