So you have seen the above image by now, right?
Let me explain the above image in short.
GaCl3 lewis structure has an Gallium atom (Ga) at the center which is surrounded by three Chlorine atoms (Cl). There are 3 single bonds between the Gallium atom (Ga) and each Chlorine atom (Cl).
If you haven’t understood anything from the above image of GaCl3 lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of GaCl3.
So let’s move to the steps of drawing the lewis structure of GaCl3.
Steps of drawing GaCl3 lewis structure
Step 1: Find the total valence electrons in GaCl3 molecule
In order to find the total valence electrons in a GaCl3 molecule, first of all you should know the valence electrons present in gallium 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 gallium as well as chlorine using a periodic table.
Total valence electrons in GaCl3 molecule
→ Valence electrons given by gallium atom:
Gallium is a group 13 element on the periodic table.  Hence the valence electrons present in gallium is 3.
You can see the 3 valence electrons present in the gallium atom as shown in the above image.
→ Valence electrons given by chlorine atom:
Chlorine is group 17 element on the periodic table.  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.
Total valence electrons in GaCl3 molecule = valence electrons given by 1 gallium atom + valence electrons given by 3 chlorine atoms = 3 + 7(3) = 24.
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 GaCl3 and it contains gallium atom (Ga) and chlorine atoms (Cl).
You can see the electronegativity values of gallium atom (Ga) and chlorine atom (Cl) in the above periodic table.
If we compare the electronegativity values of gallium (Ga) and chlorine (Cl) then the gallium atom is less electronegative.
So here the gallium atom (Ga) 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 GaCl3 molecule, you have to put the electron pairs between the gallium atom (Ga) and chlorine atoms (Cl).
This indicates that the gallium (Ga) and chlorine (Cl) are chemically bonded with each other in a GaCl3 molecule.
Step 4: Make the outer atoms stable
Now in this step, you have to check the stability of the outer atoms.
Here in the sketch of GaCl3 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 GaCl3 molecule.
The GaCl3 molecule has a total 24 valence electrons and all these valence electrons are used in the above sketch of GaCl3.
Hence there are no remaining electron pairs to be kept on the central atom.
So 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 GaCl3.
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 gallium (Ga) atom as well as chlorine (Cl) atoms present in the GaCl3 molecule.
For calculating the formal charge, you have to use the following formula;
Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons
For Gallium (Ga) atom:
Valence electrons = 3 (because gallium is in group 13)
Bonding electrons = 6
Nonbonding electrons = 0
For Chlorine (Cl) atom:
Valence electron = 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 gallium (Ga) atom as well as chlorine (Cl) atom has a “zero” formal charge.
This indicates that the above lewis structure of GaCl3 is stable and there is no further change in the above structure of GaCl3.
In the above lewis dot structure of GaCl3, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of GaCl3.
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:
|NSF Lewis Structure
|C2H4Br2 Lewis Structure
|CO2 lewis structure
|SO2 lewis structure
|NO2 lewis structure
|NH3 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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