So you have seen the above image by now, right?
Let me explain the above image in short.
MgF2 lewis structure has a Magnesium atom (Mg) at the center which is surrounded by two Fluorine atoms (F). There are 2 single bonds between the Magnesium atom (Mg) and each Fluorine atom (F). There are 3 lone pairs on both the Fluorine atoms (F).
If you haven’t understood anything from the above image of MgF2 (magnesium difluoride) lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of MgF2.
So let’s move to the steps of drawing the lewis structure of MgF2.
Steps of drawing MgF2 lewis structure
Step 1: Find the total valence electrons in MgF2 molecule
In order to find the total valence electrons in a MgF2 (magnesium difluoride) molecule, first of all you should know the valence electrons present in magnesium atom as well as fluorine 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 magnesium as well as fluorine using a periodic table.
Total valence electrons in MgF2 molecule
→ Valence electrons given by magnesium atom:
Magnesium is a group 2 element on the periodic table.  Hence the valence electrons present in magnesium is 2.
You can see the 2 valence electrons present in the magnesium atom as shown in the above image.
→ Valence electrons given by fluorine atom:
Fluorine is group 17 element on the periodic table.  Hence the valence electron present in fluorine is 7.
You can see the 7 valence electrons present in the fluorine atom as shown in the above image.
Total valence electrons in MgF2 molecule = valence electrons given by 1 magnesium atom + valence electrons given by 2 fluorine 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 MgF2 (magnesium difluoride) and it contains magnesium atom (Mg) and fluorine atoms (F).
You can see the electronegativity values of magnesium atom (Mg) and fluorine atom (F) in the above periodic table.
If we compare the electronegativity values of magnesium (Mg) and fluorine (F) then the magnesium atom is less electronegative.
So here the magnesium atom (Mg) is the center atom and the fluorine atoms (F) are the outside atoms.
Step 3: Connect each atoms by putting an electron pair between them
Now in the MgF2 molecule, you have to put the electron pairs between the magnesium atom (Mg) and fluorine atoms (F).
This indicates that the magnesium (Mg) and fluorine (F) are chemically bonded with each other in a MgF2 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 MgF2 molecule, you can see that the outer atoms are fluorine atoms.
These outer fluorine 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 MgF2 molecule.
The MgF2 molecule has a total 16 valence electrons and all these valence electrons are used in the above sketch of MgF2.
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 magnesium atom (Mg) is stable or not.
Now magnesium requires only 4 electrons to become stable. The s-orbitals of magnesium get completely filled by these 4 electrons.
You can see from the above picture that the magnesium atom has 4 electrons and hence it is stable.
Now let’s proceed to the final step to check whether the lewis structure of MgF2 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 MgF2.
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 magnesium (Mg) atom as well as fluorine (F) atoms present in the MgF2 molecule.
For calculating the formal charge, you have to use the following formula;
Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons
For Magnesium (Mg) atom:
Valence electrons = 2 (because magnesium is in group 2)
Bonding electrons = 4
Nonbonding electrons = 0
For Fluorine (F) atom:
Valence electron = 7 (because fluorine is in group 17)
Bonding electrons = 2
Nonbonding electrons = 6
From the above calculations of formal charge, you can see that the magnesium (Mg) atom as well as fluorine (F) atom has a “zero” formal charge.
This indicates that the above lewis structure of MgF2 is stable and there is no further change in the above structure of MgF2.
In the above lewis dot structure of MgF2, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of MgF2.
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:
|SbF3 Lewis Structure
|Cl3- Lewis Structure
|PCl2- Lewis Structure
|AsO2- Lewis Structure
|SBr4 Lewis Structure
|BrCl5 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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