SO Lewis Structure in 5 Steps (With Images)

So you have seen the above image by now, right?

Let me explain the above image in short.

SO lewis structure has one Sulfur atom (S) and one Oxygen atom (O) which contain a double bond between them. There are 2 lone pairs on the Sulfur atom (S) as well as Oxygen atom (O).

If you haven’t understood anything from the above image of SO lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of SO.

So let’s move to the steps of drawing the lewis structure of SO.

Steps of drawing SO lewis structure

Step 1: Find the total valence electrons in SO molecule

In order to find the total valence electrons in SO molecule, first of all you should know the valence electrons present in a sulfur atom as well as oxygen atom.
(Valence electrons are the electrons that are present in the outermost orbit of any atom.)

Here, I’ll tell you how you can easily find the valence electrons of sulfur as well as oxygen using a periodic table.

Total valence electrons in SO molecule

→ Valence electrons given by sulfur atom:

Sulfur is a group 16 element on the periodic table. ^[1] Hence the valence electrons present in sulfur is 6.

You can see the 6 valence electrons present in the sulfur atom as shown in the above image.

→ Valence electrons given by oxygen atom:

Oxygen is group 16 element on the periodic table. ^[2] Hence the valence electrons present in oxygen is 6.

You can see the 6 valence electrons present in the oxygen atom as shown in the above image.

Hence, 

Total valence electrons in SO molecule = valence electrons given by 1 sulfur atom + valence electrons given by 1 oxygen atom = 6 + 6 = 12.

Step 2: Select the central atom

For selecting the center atom, you have to remember that the atom which is less electronegative remains at the center.

Now here the given molecule is SO. It has only two atoms, so you can select any of the atoms as a center atom.

Let’s assume the oxygen atom as a central atom.

Step 3: Connect each atoms by putting an electron pair between them

Now in the SO molecule, you have to put the electron pairs between the sulfur atom (S) and oxygen atom (O).

This indicates that the sulfur (S) atom and oxygen (O) atom are chemically bonded with each other in a SO molecule.

Step 4: Make the outer atoms stable. Place the remaining valence electrons pair on the central atom.

Now in this step, you have to check the stability of the outer atom.

Here in the sketch of SO molecule, we have assumed the oxygen atom as a center atom. So the sulfur is the outer atom.

Hence you have to make the sulfur atom stable.

You can see in the below image that the sulfur atom is forming an octet and hence it is stable.

Also, in step 1 we have calculated the total number of valence electrons present in the SO molecule.

The SO molecule has a total 12 valence electrons and out of these, only 8 valence electrons are used in the above sketch.

So the number of electrons which are left = 12 – 8 = 4.

You have to put these 4 electrons on the oxygen atom in the above sketch of SO molecule.

Now let’s proceed to the next step.

Step 5: Check the octet on the central atom. If it does not have octet, then shift the lone pair to form a double bond or triple bond.

In this step, you have to check whether the central oxygen atom (O) is stable or not.

In order to check the stability of this oxygen (O) atom, we have to check whether it is forming an octet or not.

Unfortunately, this oxygen atom is not forming an octet here. Oxygen has only 6 electrons and it is unstable.

Now to make this oxygen atom stable, you have to shift the electron pair from the sulfur atom.

After shifting this electron pair, the oxygen atom will get 2 more electrons and thus its total electrons will become 8.

You can see from the above picture that the oxygen atom is forming an octet.

And hence this oxygen atom is stable.

Now let’s proceed to the final step to check whether the lewis structure of SO is stable or not.

Step 6: Check the stability of lewis structure

Now you have come to the final step in which you have to check the stability of lewis structure of SO.

The stability of lewis structure can be checked by using a concept of formal charge.

In short, now you have to find the formal charge on the sulfur atom (S) and oxygen atom (O) present in the SO molecule.

For calculating the formal charge, you have to use the following formula;

Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons

You can see the number of bonding electrons and nonbonding electrons in the image given below.

For Sulfur (S) atom:
Valence electrons = 6 (because sulfur is in group 16)
Bonding electrons = 4
Nonbonding electrons = 4

For Oxygen (O) atom:
Valence electrons = 6 (because oxygen is in group 16)
Bonding electrons = 4
Nonbonding electrons = 4

Formal charge	=	Valence electrons	–	(Bonding electrons)/2	–	Nonbonding electrons
S	=	6	–	4/2	–	4	=	0
O	=	6	–	4/2	–	4	=	0

From the above calculations of formal charge, you can see that the sulfur (S) atom and oxygen (O) atoms have a “zero” formal charge.

This indicates that the above lewis structure of SO is stable and there is no further change in the above structure of SO.

In the above lewis dot structure of SO, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of SO.

I hope you have completely understood all the above steps.

For more practice and better understanding, you can try other lewis structures listed below.

Try (or at least See) these lewis structures for better understanding:

SeF2 Lewis Structure	C2F2 Lewis Structure
XeCl4 Lewis Structure	AlBr3 Lewis Structure
AlF3 Lewis Structure	IBr Lewis Structure