KrF2 Lewis Structure in 5 Steps (With Images)

So you have seen the above image by now, right?

Let me explain the above image in short.

KrF2 lewis structure has Krypton atom (Kr) at the center which is surrounded by two Fluorine atoms (F). There are 2 single bonds between the Krypton atom (Kr) and each Fluorine atom (F). There are 3 lone pairs on the Krypton atom (Kr) as well as on both the Fluorine atoms (F).

If you haven’t understood anything from the above image of KrF2 lewis structure, then just stick with me and you will get the detailed step by step explanation on drawing a lewis structure of KrF2.

So let’s move to the steps of drawing the lewis structure of KrF2.

Steps of drawing KrF2 lewis structure

Step 1: Find the total valence electrons in KrF2 molecule

In order to find the total valence electrons in a KrF2 molecule, first of all you should know the valence electrons present in krypton 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 krypton as well as fluorine using a periodic table.

Total valence electrons in KrF2 molecule

→ Valence electrons given by krypton atom:

Krypton is a group 18 element on the periodic table. ^[1] Hence the valence electrons present in krypton is 8.

You can see the 8 valence electrons present in the krypton 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.

Hence, 

Total valence electrons in KrF2 molecule = valence electrons given by 1 krypton atom + valence electrons given by 2 fluorine atoms = 8 + 7(2) = 22.

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 KrF2 and it contains krypton atom (Kr) and fluorine atoms (F).

You can see the electronegativity values of krypton atom (Kr) and fluorine atom (F) in the above periodic table.

If we compare the electronegativity values of krypton (Kr) and fluorine (F) then the krypton atom is less electronegative.

So here the krypton atom (Kr) 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 KrF2 molecule, you have to put the electron pairs between the krypton atom (Kr) and fluorine atoms (F).

This indicates that the krypton (Kr) and fluorine (F) are chemically bonded with each other in a KrF2 molecule.

Step 4: Make the outer atoms stable. Place the remaining valence electrons pair on the central atom.

Now in this step, you have to check the stability of the outer atoms.

Here in the sketch of KrF2 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 KrF2 molecule.

The KrF2 molecule has a total 22 valence electrons and out of these, only 16 valence electrons are used in the above sketch.

So the number of electrons which are left = 22 – 16 = 6.

You have to put these 6 electrons on the central krypton atom in the above sketch of KrF2 molecule.

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 KrF2.

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 krypton (Kr) atom as well as fluorine (F) atoms present in the KrF2 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 KrF2 molecule in the image given below.

For Krypton (Kr) atom:
Valence electrons = 8 (because krypton is in group 18)
Bonding electrons = 4
Nonbonding electrons = 6

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 krypton (Kr) atom as well as fluorine (F) atom has a “zero” formal charge.

This indicates that the above lewis structure of KrF2 is stable and there is no further change in the above structure of KrF2.

In the above lewis dot structure of KrF2, you can also represent each bonding electron pair (:) as a single bond (|). By doing so, you will get the following lewis structure of KrF2.

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:

About author

Jay Rana

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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