Question

How do you draw the lewis structure for polyatomic ions?

Answer 1

Well you use [VESPER....](https://socratic.org/questions/how-does-vsepr-theory-classify-molecules)

Explanation:

And `"VSEPR"-="Valence shell electron pair repulsion theory."`

And I will give ONE bond, the VESPER treatment of nitrate ion...we gots `NO_3^(-)`...and there are ……

`3xx6_"oxygen valence electrons"+5_"nitrogen valence electrons"+1_"negative charge"` `="24 electrons"`, i.e. TWELVE electron pairs to distribute over FOUR CENTRES....

And we get....`O=stackrel(+)N(-O^(-))_2`...THREE of the four participating atoms have a formal charge...the leftmost oxygen is NEUTRAL (it has 8 electrons), the nitrogen has SIX electrons, and therefore has a FORMAL POSITIVE charge...and two of the oxygens bear 9 electrons, and thus have a FORMAL NEGATIVE charge... The overall charge is this `+1-1-1=-1`.

Can you try for `SO_4^(2-)`?