BrCl3 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.

BrCl3 lewis structure has an Bromine atom (Br) at the center which is surrounded by three Chlorine atoms (Cl). There are 3 single bonds between the Bromine atom (Br) and each Chlorine atom (Cl). There are 2 lone pairs on the Bromine atom (Br) and 3 lone pairs on all three Chlorine atoms (Cl).

If you haven’t understood anything from the above image of BrCl3 lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of BrCl3.

So let’s move to the steps of drawing the lewis structure of BrCl3.

Steps of drawing BrCl3 lewis structure

Step 1: Find the total valence electrons in BrCl3 molecule

In order to find the total valence electrons in a BrCl3 molecule, first of all you should know the valence electrons present in the bromine atom as well as chlorine 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 as well as chlorine using a periodic table.

Total valence electrons in BrCl3 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.

→ Valence electrons given by chlorine atom:

Chlorine is group 17 element on the periodic table. ^[2] Hence the valence electrons present in chlorine is 7.

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

Hence, 

Total valence electrons in BrCl3 molecule = valence electrons given by 1 bromine atom + valence electrons given by 3 chlorine atoms = 7 + 7(3) = 28.

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 BrCl3 (bromine trichloride) and it contains bromine atom (Br) and chlorine atoms (Cl).

You can see the electronegativity values of bromine atom (Br) and chlorine atom (Cl) in the above periodic table.

If we compare the electronegativity values of bromine (Br) and chlorine (Cl) then the bromine atom is less electronegative.

So here the bromine atom (Br) is the center atom and the chlorine atoms (Cl) are the outside atoms.

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

Now in the BrCl3 molecule, you have to put the electron pairs between the bromine atom (Br) and chlorine atoms (Cl).

This indicates that the bromine (Br) and chlorine (Cl) are chemically bonded with each other in a BrCl3 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 BrCl3 molecule, you can see that the outer atoms are chlorine atoms.

These outer chlorine 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 BrCl3 molecule.

The BrCl3 molecule has a total 28 valence electrons and out of these, only 24 valence electrons are used in the above sketch.

So the number of electrons which are left = 28 – 24 = 4.

You have to put these 4 electrons on the central bromine atom in the above sketch of BrCl3 molecule.

Now let’s proceed to the next step.

Step 5: 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 BrCl3.

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 bromine (Br) atom as well as chlorine (Cl) atoms present in the BrCl3 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 BrCl3 molecule in the image given below.

For Bromine (Br) atom:
Valence electrons = 7 (because bromine is in group 17)
Bonding electrons = 6
Nonbonding electrons = 4

For Chlorine (Cl) atom:
Valence electrons = 7 (because chlorine is in group 17)
Bonding electrons = 2
Nonbonding electrons = 6

From the above calculations of formal charge, you can see that the bromine (Br) atom as well as chlorine (Cl) atom has a “zero” formal charge.

This indicates that the above lewis structure of BrCl3 is stable and there is no further change in the above structure of BrCl3.

In the above lewis dot structure of BrCl3, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of BrCl3.

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:

About author

Jay Rana

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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