So you have seen the above image by now, right?
Let me explain the above image in short.
AsF5 lewis structure has an Arsenic atom (As) at the center which is surrounded by five Fluorine atoms (F). There are 5 single bonds between the Arsenic atom (As) and each Fluorine atom (F).
If you haven’t understood anything from the above image of AsF5 lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of AsF5.
So let’s move to the steps of drawing the lewis structure of AsF5.
Steps of drawing AsF5 lewis structure
Step 1: Find the total valence electrons in AsF5 molecule
In order to find the total valence electrons in an AsF5 molecule, first of all you should know the valence electrons present in arsenic 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 arsenic as well as fluorine using a periodic table.
Total valence electrons in AsF5 molecule
→ Valence electrons given by arsenic atom:
Arsenic is a group 15 element on the periodic table.  Hence the valence electrons present in arsenic is 5.
You can see the 5 valence electrons present in the arsenic 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 AsF5 molecule = valence electrons given by 1 arsenic atom + valence electrons given by 5 fluorine atoms = 5 + 7(5) = 40.
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 AsF5 and it contains arsenic atom (As) and fluorine atoms (F).
You can see the electronegativity values of arsenic atom (As) and fluorine atom (F) in the above periodic table.
If we compare the electronegativity values of arsenic (As) and fluorine (F) then the arsenic atom is less electronegative.
So here the arsenic atom (As) 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 AsF5 molecule, you have to put the electron pairs between the arsenic atom (As) and fluorine atoms (F).
This indicates that the arsenic (As) and fluorine (F) are chemically bonded with each other in a AsF5 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 AsF5 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 AsF5 molecule.
The AsF5 molecule has a total 40 valence electrons and all these valence electrons are used in the above sketch of AsF5.
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 AsF5.
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 arsenic (As) atom as well as fluorine (F) atoms present in the AsF5 molecule.
For calculating the formal charge, you have to use the following formula;
Formal charge = Valence electrons – (Bonding electrons)/2 – Nonbonding electrons
For Arsenic (As) atom:
Valence electrons = 5 (because arsenic is in group 15)
Bonding electrons = 10
Nonbonding electrons = 0
For Fluorine (F) atom:
Valence electrons = 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 arsenic (As) atom as well as fluorine (F) atom has a “zero” formal charge.
This indicates that the above lewis structure of AsF5 is stable and there is no further change in the above structure of AsF5.
In the above lewis dot structure of AsF5, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of AsF5.
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:
|PO3- Lewis Structure
|BBr3 Lewis Structure
|IF2- Lewis Structure
|BrF2- Lewis Structure
|P2 Lewis Structure
|IBr2- 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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