Lewis structure of KrF2

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The Lewis structure of KrF₂ contains two single bonds, with krypton in the center, and two fluorines on either side. There are three lone pairs on each atom.

Steps

By using the following steps, you can easily draw the Lewis structure of KrF₂.

#1 Draw skeleton
#2 Show chemical bond
#3 Mark lone pairs
#4 Calculate formal charge and check stability (if octet is already completed on central atom)

Let’s one by one discuss each step in detail.

#1 Draw skeleton

In this step, first calculate the total number of valence electrons. And then, decide the central atom.

• Let’s calculate the total number of valence electrons

We know that… krypton is a group 18 element and fluorine is a group 17 element. Hence, krypton has eight valence electrons and fluorine has seven valence electrons.

Now KrF₂ has one krypton atom and two fluorine atoms.

So the total number of valence electrons = valence electrons of krypton atom + (valence electrons of fluorine atom × 2)

Therefore, the total number of valence electrons = 8 + 14 = 22

• Now decide the central atom

The atom with the least electronegative value is placed at the center. By looking at the periodic table, we get the electronegativity values for krypton and fluorine as follows:

Electronegativity value of krypton = 3.00
Electronegativity value of fluorine = 3.98

Obviously, krypton is less electronegative than fluorine. Hence, assume that krypton is the central atom.

So now, put krypton in the center and fluorines on either side. And draw the rough skeleton structure for the Lewis structure of KrF₂ something like this:

Also read: How to draw Lewis structure of N₂F₂ (5 steps)

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since krypton is surrounded by two fluorines, use four electrons to show two chemical bonds as follows:

Also read: How to draw Lewis structure of XeOF₄ (5 steps)

#3 Mark lone pairs

As calculated earlier, we have a total of 22 valence electrons. And in the above structure, we have already used four valence electrons. Hence, eighteen valence electrons are remaining.

Two valence electrons represent one lone pair. So eighteen valence electrons = nine lone pairs.

Note that krypton is a period 4 element, so it can keep more than 8 electrons in its last shell. And fluorine is a period 2 element, so it can not keep more than 8 electrons in its last shell.

Also, make sure that you start marking these lone pairs on outside atoms first. And then, on the central atom.

The outside atoms are fluorines, so each fluorine will get three lone pairs. And the central atom (krypton) will also get three lone pairs.

So the Lewis structure of KrF₂ looks something like this:

In the above structure, you can see that the octet is completed on the central atom (krypton), and also on the outside atoms. Therefore, the octet rule is satisfied.

After completing the octet, one last thing we need to do is, calculate the formal charge and check the stability of the above structure.

Also read: How to draw Lewis structure of BrCl₃ (4 steps)

#4 Calculate formal charge and check stability

The following formula is used to calculate the formal charges on atoms:

Formal charge = valence electrons – nonbonding electrons – ½ bonding electrons

Collect the data from the above structure and then, write it down below as follows:

• For krypton atom

Valence electrons = 8
Nonbonding electrons = 6
Bonding electrons = 4

Formal charge = 8 – 6 – ½ (4) = 0

• For each fluorine atom

Valence electrons = 7
Nonbonding electrons = 6
Bonding electrons = 2

Formal charge = 7 – 6 – ½ (2) = 0

Mention the formal charges of atoms on the structure. So the Lewis structure of KrF₂ looks something like this:

In the above structure, you can see that the formal charges of both (krypton and fluorine) are zero. Therefore, this is the stable Lewis structure of KrF₂.

And each horizontal line drawn in the above structure represents a pair of bonding valence electrons.

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Related

• Lewis structure of N₂F₂
• Lewis structure of XeOF₄
• Lewis structure of BrCl₃
• Lewis structure of CSe₂
• Lewis structure of BeBr₂

External video

• KrF2 Lewis Structure: How to Draw the Lewis Structure for KrF2 (Krypton Difluoride) – YouTube • Wayne Breslyn

External links

• KrF2 Lewis Structure, Hybridization, Molecular Geometry, and Polarity – Techiescientist
• KrF2 Lewis Structure in 5 Steps (With Images) – Pediabay
• What is the Lewis Dot Structure KrF2? How is it determined? – Quora
• Draw the Lewis Structure for KrF2. The central atom has _____ lone pairs – Chegg
• Draw the Lewis structures for KrF₂ that obey the octet rule and show all resonance forms – Homework.Study.com
• Is KrF2 Polar or Nonpolar? – Science Coverage
• Krypton difluoride – Wikipedia
• Draw the Lewis structure for KrF2. Determine its geometry and the formal charges of its atoms – Numerade