Chemistry Forum

please help me with: In the Lewis structure of Sulphuric Acid, what is the total number of electrons in the covalent bonds surrounding the sulphur atom? thanks.

In the Lewis model for sulfate ion, sulfur has a formal 2+ charge, and each oxygen a 1- charge, connecting them by four ionic bonds.

However, this is usually represented in valence dot diagrams by the Pauling model: sulfur connected to each oxygen by two single bonds, and two double bonds (12 shared electrons). The oxygen atoms connected to sulfur by the single bond have three additional pairs of electrons (ie: 6 valence + 2 shared each), while the oxygen atoms connected by double bonds have two valence pairs (ie; 4 valence + 4 shared each). This considered a resonance structure.

Something like this:

░░░••░[2-]░░░░░░░░░░
â–‘â–‘: O :â–‘â–‘â–‘â–‘â–‘â–‘â–‘â–‘: O :â–‘[2-]
░••░│░••░░░░░░••░║░••░
â–‘Oâ•Sâ•Oâ–‘<=>â–‘â–‘: O─S─O :
░••░│░••░░░░░░••░║░••░
â–‘â–‘: O :â–‘â–‘â–‘â–‘â–‘â–‘â–‘â–‘: O :â–‘â–‘
░░░••░░░░░░░░░░░░░


(It's 12 because Sulfur can expand its "valence octet" into the 3d orbital.)

Mr. Graham Kemp, thanks a lot for your reply. question: count the total number of electrons in the covalent bonds surrounding the sulphur atom in Sulphate Ion. How can one argue for its expected answer ie '6'. If i count the total number of electrons that surround the sulphur atom, then it is 12 as you replied. But how will i explain that its Six and Not twelve (if possible)?

appelsinbla wrote:Mr. Graham Kemp, thanks a lot for your reply. question: count the total number of electrons in the covalent bonds surrounding the sulphur atom in Sulphate Ion. How can one argue for its expected answer ie '6'. If i count the total number of electrons that surround the sulphur atom, then it is 12 as you replied. But how will i explain that its Six and Not twelve (if possible)?

Why do you expect the answer to be 6?

That's the number of valence bonds in the Pauling model. With each bond being comprised of 2 shared electrons, that's 12 total.