So you have seen the above image by now, right?
Let me explain the above image in short.
BeCl2 lewis structure has a Beryllium atom (Be) at the center which is surrounded by two Chlorine atoms (Cl). There are 2 single bonds between the Beryllium atom (Be) and each Chlorine atom (Cl). There are 3 lone pairs on both the Chlorine atoms (Cl).
If you haven’t understood anything from the above image of BeCl2 (beryllium dichloride) lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of BeCl2.
So let’s move to the steps of drawing the lewis structure of BeCl2.
Steps of drawing BeCl2 lewis structure
Step 1: Find the total valence electrons in BeCl2 molecule
In order to find the total valence electrons in a BeCl2 (beryllium dichloride) molecule, first of all you should know the valence electrons present in beryllium 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 beryllium as well as chlorine using a periodic table.
Total valence electrons in BeCl2 molecule
→ Valence electrons given by beryllium atom:
Beryllium is a group 2 element on the periodic table.  Hence the valence electrons present in beryllium is 2.
You can see the 2 valence electrons present in the beryllium 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 BeCl2 molecule = valence electrons given by 1 beryllium atom + valence electrons given by 2 chlorine atoms = 2 + 7(2) = 16.
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 BeCl2 (beryllium dichloride) and it contains beryllium atom (Be) and chlorine atoms (Cl).
You can see the electronegativity values of beryllium atom (Be) and chlorine atom (Cl) in the above periodic table.
If we compare the electronegativity values of beryllium (Be) and chlorine (Cl) then the beryllium atom is less electronegative.
So here the beryllium atom (Be) 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 BeCl2 molecule, you have to put the electron pairs between the beryllium atom (Be) and chlorine atoms (Cl).
This indicates that the beryllium (Be) and chlorine (Cl) are chemically bonded with each other in a BeCl2 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 BeCl2 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 BeCl2 molecule.
The BeCl2 molecule has a total 16 valence electrons and all these valence electrons are used in the above sketch of BeCl2.
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 the central atom
In this step, you have to check whether the central beryllium atom (Be) is stable or not.
Now beryllium requires only 4 electrons to become stable. The s-orbitals of beryllium get completely filled by these 4 electrons.
You can see from the above picture that the beryllium atom has 4 electrons and hence it is stable.
Now let’s proceed to the final step to check whether the lewis structure of BeCl2 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 BeCl2.
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 beryllium (Be) atom as well as chlorine (Cl) atoms present in the BeCl2 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 BeCl2 molecule in the image given below.
For Beryllium (Be) atom:
Valence electrons = 2 (because beryllium is in group 2)
Bonding electrons = 4
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 beryllium (Be) atom as well as chlorine (Cl) atom has a “zero” formal charge.
This indicates that the above lewis structure of BeCl2 is stable and there is no further change in the above structure of BeCl2.
In the above lewis dot structure of BeCl2, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of BeCl2.
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:
|Acetone (C3H6O) Lewis Structure
|POCl3 Lewis Structure
|HNO2 Lewis Structure
|HCO3- Lewis Structure
|C3H8 (Propane) Lewis Structure
|CH3CN 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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