So you have seen the above image by now, right?
Let me explain the above image in short.
Br2 lewis structure has two Bromine atoms (Br) which contain a single bond between them. There are 3 lone pairs on both the Bromine atoms (Br).
If you haven’t understood anything from the above image of Br2 (bromine) lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of Br2.
So let’s move to the steps of drawing the lewis structure of Br2.
Steps of drawing Br2 lewis structure
Step 1: Find the total valence electrons in Br2 molecule
In order to find the total valence electrons in a Br2 (bromine) molecule, first of all you should know the valence electrons present in a single 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 bromine using a periodic table.
Total valence electrons in Br2 molecule
→ Valence electrons given by bromine atom:
Bromine is a group 17 element on the periodic table. [1] 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 Br2 molecule = 7(2) = 14.
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 Br2 (bromine). Both the atoms are same, so you can select any of the atoms as a center atom.
Let’s assume the right side bromine as a central atom.
Step 3: Connect each atoms by putting an electron pair between them
Now in the Br2 molecule, you have to put the electron pairs between both the bromine atoms (Br).
This indicates that both the bromine (Br) atoms are chemically bonded with each other in a Br2 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 Br2 molecule, we have assumed the right side bromine atom as a center atom. So the left side bromine is the outer atom.
Hence you have to make the left side bromine stable.
You can see in the below image that the left side bromine 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 Br2 molecule.
The Br2 molecule has a total 14 valence electrons and out of these, only 8 valence electrons are used in the above sketch.
So the number of electrons which are left = 14 – 8 = 6.
You have to put these 6 electrons on the right side bromine atom in the above sketch of Br2 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 (i.e right side) bromine atom (Br) is stable or not.
In order to check the stability of this bromine (Br) atom, we have to check whether it is forming an octet or not.
You can see from the above picture that both the bromine atoms are forming an octet. That means they have 8 electrons.
And hence the bromine atoms are stable.
Now let’s proceed to the final step to check whether the lewis structure of Br2 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 Br2.
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 both the bromine (Br) atoms present in the Br2 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 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 | ||
Br | = | 7 | – | 2/2 | – | 6 | = | 0 |
From the above calculations of formal charge, you can see that both the bromine (Br) atoms have a “zero” formal charge.
This indicates that the above lewis structure of Br2 is stable and there is no further change in the above structure of Br2.
In the above lewis dot structure of Br2, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of Br2.
I hope you have completely understood all the above steps.
For more practice and better understanding, you can try other lewis structures listed below.
I hope you have completely understood all the above steps.
Try (or at least See) these lewis structures for better understanding:
BeCl2 Lewis Structure | CH3COO- Lewis Structure |
Acetone (C3H6O) Lewis Structure | POCl3 Lewis Structure |
HNO2 Lewis Structure | HCO3- Lewis Structure |
Jay is an educator and has helped more than 100,000 students in their studies by providing simple and easy explanations on different science-related topics. He is a founder of Pediabay and is passionate about helping students through his easily digestible explanations.
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