In the sulfate ion (#SO_4^(2-)#), how many electrons are available for bonding?

1 Answer
Dec 3, 2016

Answer:

There are #5xx6+2=32# #"valence electrons"#, distributed around 5 centres. #12# electrons are formally involved in bonding.

Explanation:

A typical valence bond representation of the #"sulfate dianion"# is as #""^(-)O_2S(=O)_2# (this derives from the parent sulfuric acid, #(HO)_2S(=O)_2#). Around the sulfur centre there are 6 valence electrons, participating in single or multiple #"sulfur-oxygen"# bonds.

What is the geometry around sulfur?

A representation of #(HO)_2""S^(2+)(O^-)_2# is also feasible, but the sulfur oxygen double bonds are usually depicted.

Note that the electron count was simply obtained by the operation #5xx6+2=32# #"valence electrons"#. Why did I add an additional 2 electrons?