So you have seen the above image by now, right?
Let me explain the above image in short.
PF2Cl3 lewis structure has a Phosphorus atom (P) at the center which is surrounded by two Fluorine atoms (F) and three Chlorine atoms (Cl). There are single bonds between the Phosphorus-Fluorine atoms and Phosphorus-Chlorine atoms. There are 3 lone pairs on the Fluorine atoms (F) as well as Chlorine atoms (Cl).
If you haven’t understood anything from the above image of PF2Cl3 lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of PF2Cl3.
So let’s move to the steps of drawing the lewis structure of PF2Cl3.
Steps of drawing PF2Cl3 lewis structure
Step 1: Find the total valence electrons in PF2Cl3 molecule
In order to find the total valence electrons in a PF2Cl3 molecule, first of all you should know the valence electrons present in phosphorus atom, fluorine 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 phosphorus, fluorine as well as chlorine using a periodic table.
Total valence electrons in PF2Cl3 molecule
→ Valence electrons given by phosphorus atom:
Phosphorus is group 15 element on the periodic table. [1] Hence the valence electrons present in phosphorus is 5.
You can see the 5 valence electrons present in the phosphorus atom as shown in the above image.
→ Valence electrons given by fluorine atom:
Fluorine is group 17 element on the periodic table. [2] 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.
→ Valence electrons given by chlorine atom:
Chlorine is group 17 element on the periodic table. [3] 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 PF2Cl3 molecule = valence electrons given by 1 phosphorus atom + valence electrons given by 2 fluorine atoms + valence electrons given by 3 chlorine atoms = 5 + 7(3) + 7(2) = 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 PF2Cl3 and it contains phosphorus atom (P), fluorine atoms (F) and chlorine atoms (Cl).
You can see the electronegativity values of phosphorus atom (P), fluorine atom (F) and chlorine atom (Cl) in the above periodic table.
If we compare the electronegativity values of phosphorus (P), fluorine (F) and chlorine (Cl) then the phosphorus atom is less electronegative.
So here the phosphorus atom (P) is the center atom and the fluorine atoms (F) & chlorine atoms (Cl) are the outside atoms.
Step 3: Connect each atoms by putting an electron pair between them
Now in the PF2Cl3 molecule, you have to put the electron pairs between the phosphorus atom (P), fluorine atoms (F) and chlorine atoms (Cl).
This indicates that the phosphorus (P), fluorine (F) and chlorine (Cl) are chemically bonded with each other in a PF2Cl3 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 PF2Cl3 molecule, you can see that the outer atoms are fluorine atoms and chlorine atoms.
These outer fluorine and 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 PF2Cl3 molecule.
The PF2Cl3 molecule has a total 40 valence electrons and all these valence electrons are used in the above sketch of PF2Cl3.
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 PF2Cl3.
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 phosphorus (P) atom, fluorine (F) atoms as well as chlorine (Cl) atoms present in the PF2Cl3 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 PF2Cl3 molecule in the image given below.
For Phosphorus (P) atom:
Valence electrons = 5 (because phosphorus 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
For Chlorine (Cl) atom:
Valence electron = 7 (because chlorine is in group 17)
Bonding electrons = 2
Nonbonding electrons = 6
Formal charge | = | Valence electrons | – | (Bonding electrons)/2 | – | Nonbonding electrons | ||
P | = | 5 | – | 10/2 | – | 0 | = | 0 |
F | = | 7 | – | 2/2 | – | 6 | = | 0 |
Cl | = | 7 | – | 2/2 | – | 6 | = | 0 |
From the above calculations of formal charge, you can see that the phosphorus (P) atom, fluorine (F) atom as well as chlorine (Cl) atom has a “zero” formal charge.
This indicates that the above lewis structure of PF2Cl3 is stable and there is no further change in the above structure of PF2Cl3.
In the above lewis dot structure of PF2Cl3, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of PF2Cl3.
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:
IBr4- Lewis Structure | SeOBr2 Lewis Structure |
HBrO2 Lewis Structure | HBrO3 Lewis Structure |
HBrO4 Lewis Structure | PO2- 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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