NOBr 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.

NOBr lewis structure has a Nitrogen atom (N) at the center which is surrounded by one Oxygen atom (O) and one Bromine atom (Br). There is a double bond between the Nitrogen (N) & Oxygen (O) atom and a single bond between the Nitrogen (N) & Bromine (Br) atom.

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

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

Steps of drawing NOBr lewis structure

Step 1: Find the total valence electrons in NOBr molecule

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

Total valence electrons in NOBr 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 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.

→ Valence electrons given by bromine atom:

Bromine is a group 17 element on the periodic table. ^[3] Hence the valence electrons present in bromine is 7.

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

Hence, 

Total valence electrons in NOBr molecule = valence electrons given by 1 nitrogen atom + valence electrons given by 1 oxygen atom + valence electrons given by 1 bromine 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 NOBr and it contains nitrogen atom (N), oxygen atom (O) and bromine atom (Br).

You can see the electronegativity values of nitrogen atom (N), oxygen atom (O) and bromine atom (Br) in the above periodic table.

If we compare the electronegativity values of nitrogen atom (N), oxygen atom (O) and bromine atom (Br) then the nitrogen atom is less electronegative.

So here the nitrogen atom is the center atom and the oxygen & bromine atoms are the outside atoms.

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

Now in the NOBr molecule, you have to put the electron pairs between the nitrogen (N) & oxygen (O) atom and between the nitrogen (N) & bromine (Br) atom.

This indicates that these atoms are chemically bonded with each other in a NOBr 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 NOBr molecule, you can see that the outer atoms are oxygen atom and bromine atom.

These oxygen atom and bromine 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 NOBr molecule.

The NOBr 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 NOBr 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 oxygen 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 NOBr 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 NOBr.

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, oxygen (O) atom as well as bromine (Br) atoms present in the NOBr 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 NOBr 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 Oxygen (O) atom:
Valence electrons = 6 (because oxygen is in group 16)
Bonding electrons = 4
Nonbonding electrons = 4

For Bromine (Br) atom:
Valence electron = 7 (because bromine 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
O	=	6	–	4/2	–	4	=	0
Br	=	7	–	2/2	–	6	=	0

From the above calculations of formal charge, you can see that the nitrogen (N) atom, oxygen (O) atom as well as bromine (Br) atom have a “zero” formal charge.

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

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

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:

ClF2- Lewis Structure	ClF4- Lewis Structure
CIF3 Lewis Structure	ClCN Lewis Structure
CH2S Lewis Structure	BrF4- Lewis Structure