NSF Lewis Structure in 6 Steps (With Images)

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

Let me explain the above image in short.

NSF lewis structure has a Nitrogen atom (N) at the center which is surrounded by one Sulfur atom (S) and one Fluorine atom (F). There is a double bond between the Nitrogen (N) & Sulfur (S) atom and a single bond between the Nitrogen (N) & Fluorine (F) atom.

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

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

Steps of drawing NSF lewis structure

Step 1: Find the total valence electrons in NSF molecule

In order to find the total valence electrons in a NSF molecule, first of all you should know the valence electrons present in nitrogen atom, sulfur atom as well as fluorine 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 nitrogen, sulfur as well as fluorine using a periodic table.

Total valence electrons in NSF molecule

→ Valence electrons given by nitrogen atom:

Nitrogen is a group 15 element on the periodic table. ^[1] Hence the valence electrons present in nitrogen is 5.

You can see the 5 valence electrons present in the nitrogen atom as shown in the above image.

→ Valence electrons given by sulfur atom:

Sulfur is a group 16 element on the periodic table. ^[2] 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 fluorine atom:

Fluorine is group 17 element on the periodic table. ^[3] Hence the valence electron present in fluorine is 7.

You can see the 7 valence electrons present in the fluorine atom as shown in the above image.

Hence, 

Total valence electrons in NSF molecule = valence electrons given by 1 nitrogen atom + valence electrons given by 1 sulfur atom + valence electrons given by 1 fluorine atom = 5 + 6 + 7 = 18.

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 NSF and it contains nitrogen atom (N), sulfur atom (S) and fluorine atom (F).

You can see the electronegativity values of nitrogen atom (N), sulfur atom (S) and fluorine atom (F) in the above periodic table.

If we compare the electronegativity values of nitrogen atom (N), sulfur atom (S) and fluorine atom (F) then the nitrogen atom is less electronegative.

So here the nitrogen atom is the center atom and the sulfur & fluorine atoms are the outside atoms.

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

Now in the NSF molecule, you have to put the electron pairs between the nitrogen (N) & sulfur (S) atom and between the nitrogen (N) & fluorine (F) atom.

This indicates that these atoms are chemically bonded with each other in a NSF 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 atoms.

Here in the sketch of NSF molecule, you can see that the outer atoms are sulfur atom and fluorine atom.

These sulfur atom and fluorine atom are forming an octet and hence they are stable.

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

The NSF molecule has a total 18 valence electrons and out of these, only 16 valence electrons are used in the above sketch.

So the number of electrons which are left = 18 – 16 = 2.

You have to put these 2 electrons on the central nitrogen atom in the above sketch of NSF 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 nitrogen atom (N) is stable or not.

In order to check the stability of the central nitrogen (N) atom, we have to check whether it is forming an octet or not.

Unfortunately, the nitrogen atom is not forming an octet here. Nitrogen has only 6 electrons and it is unstable.

Now to make this nitrogen atom stable, you have to shift the electron pair from the outer sulfur atom so that the nitrogen atom can have 8 electrons (i.e octet).

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

You can see from the above picture that the nitrogen atom is forming an octet as it has 8 electrons.

Now let’s proceed to the final step to check whether the lewis structure of NSF 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 NSF.

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 nitrogen (N) atom, sulfur (S) atom as well as fluorine (F) atoms present in the NSF 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 for each atom of NSF molecule in the image given below.

For Nitrogen (N) atom:
Valence electrons = 5 (because nitrogen is in group 15)
Bonding electrons = 6
Nonbonding electrons = 2

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

For Fluorine (F) atom:
Valence electron = 7 (because fluorine is in group 17)
Bonding electrons = 2
Nonbonding electrons = 6

Formal charge	=	Valence electrons	–	(Bonding electrons)/2	–	Nonbonding electrons
N	=	5	–	6/2	–	2	=	0
S	=	6	–	4/2	–	4	=	0
F	=	7	–	2/2	–	6	=	0

From the above calculations of formal charge, you can see that the nitrogen (N) atom, sulfur (S) atom as well as fluorine (F) atom have a “zero” formal charge.

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

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

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:

CO2 lewis structure	SO2 lewis structure
NO2 lewis structure	NH3 lewis structure
HCN lewis structure	H2O lewis structure