Cl_{3}^{–} has **three chlorine** atoms.

In Cl_{3}^{–} Lewis structure, there are two single bonds around the chlorine atom, with two other chlorine atoms attached to it, and on each chlorine atom, there are three lone pairs.

Also, there is a negative (-1) charge on the center chlorine atom.

## Steps

To properly draw the Cl_{3}^{–} Lewis structure, follow these steps:

#1 Draw a rough sketch of the structure

#2 Next, indicate lone pairs on the atoms

#3 Indicate formal charges on the atoms, if necessary

Let’s break down each step in more detail.

### #1 Draw a rough sketch of the structure

- First, determine the total number of valence electrons

In the periodic table, chlorine lies in group 17. Hence, chlorine has **seven** valence electrons.

Since Cl_{3}^{–} has three chlorine atoms, so…

Valence electrons of three chlorine atoms = 7 × 3 = 21

Now the Cl_{3}^{–} has a negative (-1) charge, so we have to add one more electron.

So the **total valence electrons** = 21 + 1 = 22

Learn how to find: Chlorine valence electrons

- Second, find the total electron pairs

We have a total of 22 valence electrons. And when we divide this value by two, we get the value of total electron pairs.

Total electron pairs = total valence electrons ÷ 2

So the **total electron pairs** = 22 ÷ 2 = 11

- Third, determine the central atom

Here, there are three atoms and all atoms are chlorine, so we can assume any one as the central atom.

Let’s assume that the **central atom is center chlorine**.

- And finally, draw the rough sketch

### #2 Next, indicate lone pairs on the atoms

Here, we have a total of 11 electron pairs. And two Cl — Cl bonds are already marked. So we have to only mark the remaining nine electron pairs as lone pairs on the sketch.

Also remember that chlorine is a period 3 element, so it can keep more than 8 electrons in its last shell.

Always start to mark the lone pairs from outside atoms. Here, the outside atoms are left chlorine and right chlorine.

So for each chlorine, there are **three** lone pairs.

Mark the lone pairs on the sketch as follows:

### #3 Indicate formal charges on the atoms, if necessary

Use the following formula to calculate the formal charges on atoms:

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

For **left chlorine** and **right chlorine** atom, formal charge = 7 – 6 – ½ (2) = 0

For **center chlorine** atom, formal charge = 7 – 6 – ½ (4) = -1

Here, the center chlorine atom has a charge, so mark it on the sketch as follows:

In the above structure, you can see that the central atom (center chlorine) forms an octet. And the outside atoms (left chlorine and right chlorine) also form an octet. Hence, the octet rule is satisfied.

Now there is still a negative (-1) charge on the center chlorine atom.

This is okay, because the structure with a negative charge on the most electronegative atom is the best Lewis structure. And in this case, the most electronegative element is chlorine.

Therefore, this structure is the **most stable Lewis structure** of Cl_{3}^{–}.

And since the Cl_{3}^{–} has a negative (-1) charge, mention that charge on the Lewis structure by drawing brackets as follows:

**Next:** PCl_{2}^{–} Lewis structure

## External links

- https://socratic.org/questions/what-is-the-lewis-structure-of-cl-3
- https://homework.study.com/explanation/draw-the-best-lewis-structure-for-cl3-1-what-is-the-formal-charge-on-the-cl.html
- https://brainly.com/question/11628954
- https://www.chegg.com/homework-help/questions-and-answers/22-draw-best-lewis-structure-cl3-formal-charge-central-cl-atom-1-b-0-c-1-d-2-e-2-23-draw-b-q37864532
- https://www.coursehero.com/tutors-problems/Chemistry/30934243-Draw-the-best-Lewis-structure-for-Cl3-and-determinethe-formal-charge-o/

Deep

Learnool.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.