Lewis structure of ClBr3

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Lewis structure of ClBr3
Lewis structure of ClBr3

The Lewis structure of ClBr3 contains three single bonds, with chlorine in the center, and three bromines on either side. There are three lone pairs on each bromine atom, and two lone pairs on the chlorine atom.

Steps

By using the following steps, you can easily draw the Lewis structure of ClBr3.

#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… both chlorine and bromine are the group 17 elements. Hence, both chlorine and bromine have seven valence electrons.

Now ClBr3 has one chlorine atom and three bromine atoms.

So the total number of valence electrons = valence electrons of chlorine atom + (valence electrons of bromine atom × 3)

Therefore, the total number of valence electrons = 7 + 21 = 28

  • 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 chlorine and bromine as follows:

Electronegativity value of chlorine = 3.16
Electronegativity value of bromine = 2.96

Obviously, chlorine is less electronegative than bromine. Hence, assume that chlorine is the central atom.

So now, put chlorine in the center and bromines on either side. And draw the rough skeleton structure for the Lewis structure of ClBr3 something like this:

Skeleton structure for Lewis structure of ClBr3

#2 Show chemical bond

Place two electrons between the atoms to show a chemical bond. Since chlorine is surrounded by three bromines, use six electrons to show three chemical bonds as follows:

Three chemical bonds shown between atoms

#3 Mark lone pairs

As calculated earlier, we have a total of 28 valence electrons. And in the above structure, we have already used six valence electrons. Hence, twenty-two valence electrons are remaining.

Two valence electrons represent one lone pair. So twenty-two valence electrons = eleven lone pairs.

Note that chlorine is a period 3 element, so it can keep more than 8 electrons in its last shell. And bromine is a period 4 element, so it can 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 bromines, so each bromine will get three lone pairs. And the central atom (chlorine) will get two lone pairs.

So the Lewis structure of ClBr3 looks something like this:

Lone pairs marked on Lewis structure of ClBr3

In the above structure, you can see that the octet is completed on the central atom (chlorine), 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.

#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 chlorine atom

Valence electrons = 7
Nonbonding electrons = 4
Bonding electrons = 6

Formal charge = 7 – 4 – ½ (6) = 0

  • For each bromine 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 ClBr3 looks something like this:

Formal charges are calculated, and got the stable Lewis structure of ClBr3

In the above structure, you can see that the formal charges of both (chlorine and bromine) are zero. Therefore, this is the stable Lewis structure of ClBr3.

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

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External links

Deep

Rootmemory.com was founded by Deep Rana, who is a mechanical engineer by profession and a blogger by passion. He has a good conceptual knowledge on different educational topics and he provides the same on this website. He loves to learn something new everyday and believes that the best utilization of free time is developing a new skill.

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