Question

Why does nitrite have a negative charge instead of a positive charge?

So I was working on some polyatomic ions concept things and I found some confusing parts. NO2 has 17 outermost shell electrons and it has to lose 1 electron to become stable (16). I know this concept is wrong but I dont know what is the correct one. So as what I considered, NO2 should be positive 1 instead of negative 1. Please help me out with this. It will help a lot. Thank you very much and sorry for my bad English.

Answer 1

Because it is the conjugate base of the weak acid `"HNO"_2`. Conjugate bases always have one less `"H"^(+)`, and thus they must have a more negative charge compared to the acid.

---

There is no specific number of electrons or any sort of electron "rule" that nitrite "follows" to become stable...

`"NO"_2^(+)` would not be nitrite, but nitrogen dioxide cation (i.e. nitronium), a completely different compound. Nitronium would instead be

`:ddot"O"=stackrel((+))"N"=ddot"O":`,

a linear polyatomic ion instead of a bent one.

`"NO"_2^(-)`, nitrite, has resonance structures, as shown below...