structure of sulphite ion

Question

Explain the structure of sulphite ion

Answer 1

Sulfite ion = SO₃^2-

Sulfur has 6 valence electrons

Each oxygen has 6 valence electrons = 6 x 3 = 18 valence electrons

The -2 charge adds 2 additional electrons

Total electrons to be used =6 + 18 + 2 = 26 electrons

To draw the Lewis structure

Place the S in the center and attache 2 O atoms with single bonds, and one O atom with a double bond.

Then place one lone pair of electrons on the central S atom. That is the Lewis strucutre.

There will be 3 resonance structure (shift the double bond to the other O atoms).

This structure will have a molecular geometry of trigonal pyramidal (bond angle ~ 107º), and the S atom is sp³ hybridized.