SeOBr2 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.

SeOBr2 lewis structure has a Selenium atom (Se) at the center which is surrounded by two Bromine atoms (Br) and one Oxygen atom (O). There is a double bond between the Selenium (Se) & Oxygen (O) atom and a single bond between the Selenium (Se) and Bromine (Br) atoms.

If you haven’t understood anything from the above image of SeOBr2 lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of SeOBr2.

So let’s move to the steps of drawing the lewis structure of SeOBr2.

Steps of drawing SeOBr2 lewis structure

Step 1: Find the total valence electrons in SeOBr2 molecule

In order to find the total valence electrons in a SeOBr2 molecule, first of all you should know the valence electrons present in selenium 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 selenium, oxygen as well as bromine using a periodic table.

Total valence electrons in SeOBr2 molecule

→ Valence electrons given by selenium atom:

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

You can see the 6 valence electrons present in the selenium 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 SeOBr2 molecule = valence electrons given by 1 selenium atom + valence electrons given by 1 oxygen atom + valence electrons given by 2 bromine atoms = 6 + 6 + 7(2) = 26.

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 SeOBr2 and it contains selenium atom (Se), oxygen atom (O) and bromine atoms (Br).

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

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

So here the selenium 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 SeOBr2 molecule, you have to put the electron pairs between the selenium (Se) & oxygen (O) atom and between the selenium (Se) & bromine (Br) atoms.

This indicates that these atoms are chemically bonded with each other in a SeOBr2 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 SeOBr2 molecule, you can see that the outer atoms are oxygen atom and bromine atoms.

These oxygen atom and bromine atoms 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 SeOBr2 molecule.

The SeOBr2 molecule has a total of 26 valence electrons and out of these, only 24 valence electrons are used in the above sketch.

So the number of electrons which are left = 26 – 24 = 2.

You have to put these 2 electrons on the central selenium atom in the above sketch of SeOBr2 molecule.

Now let’s proceed to the next step.

Step 5: Check the octet on the central atom

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

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

You can see from the above picture that the selenium atom is forming an octet. That means it has 8 electrons.

And hence the central selenium atom is stable.

Now let’s proceed to the final step to check whether the lewis structure of SeOBr2 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 SeOBr2.

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 selenium (Se) atom, oxygen (O) atom as well as bromine (Br) atoms present in the SeOBr2 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 SeOBr2 molecule in the image given below.

For Selenium (Se) atom:
Valence electrons = 6 (because selenium is in group 16)
Bonding electrons = 6
Nonbonding electrons = 2

For Oxygen (O) atom:
Valence electrons = 6 (because oxygen is in group 16)
Bonding electrons = 2
Nonbonding electrons = 6

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
Se	=	6	–	6/2	–	2	=	+1
O	=	6	–	2/2	–	6	=	-1
Br	=	7	–	2/2	–	6	=	0

From the above calculations of formal charge, you can see that the selenium (Se) atom has +1 charge and the oxygen (O) atom has -1 charge.

Because of this reason, the above obtained lewis structure of SeOBr2 is not stable.

So we have to minimize these charges by shifting the electron pair towards the selenium atom.

After shifting the electron pair from oxygen atom to selenium atom, the lewis structure of SeOBr2 becomes more stable.

In the above lewis dot structure of SeOBr2, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of SeOBr2.

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:

HBrO2 Lewis Structure	HBrO3 Lewis Structure
HBrO4 Lewis Structure	PO2- Lewis Structure
TeF5- Lewis Structure	SeCl6 Lewis Structure