Chlorine Valence Electrons (And How to Find them?)

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

Awesome! You can see that chlorine has 7 valence electrons.

But how can you say that Chlorine has 7 valence electrons
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How can you find these valence electrons?

Let’s discuss this in short.

Chlorine has 7 valence electrons because there are 7 electrons present in the outermost shell of the Chlorine (Cl) atom.

Now let’s see how you can easily find the valence electrons of Chlorine atom (Cl).

If you don’t want to read the texts, then you can also watch this video.

How to find the Valence Electrons? (2 Methods)

In order to find the valence electrons of Chlorine atom (Cl), you can use two methods.

Method 1: From the Periodic Table

To find out the valence electrons of Chlorine, you have to see the position of chlorine in the periodic table.

More specifically, you have to see the group wise position of Chlorine element in the periodic table.

From the above image, you can see that the Chlorine (Cl) is present in the group 17 of periodic table.
(Note: Group 17 is also called group 7A).

So, as the chlorine element is present in group 17, it has 7 valence electrons.

In this way, by knowing the position of chlorine element in periodic table, you can easily find its valence electrons.

Now let’s see another method for finding the number of valence electrons in chlorine.

Method 2: From the Electron Configuration

If you want to find the valence electrons of chlorine from its electron configuration, then you should know its electron configuration first.

Now there are many methods to write the electron configurations, but here I will show you the easiest method, i.e by using Aufbau principle.

Aufbau principle: The Aufbau principle simply states that the orbitals with the lower energy are filled first and then the orbitals with higher energy levels are filled.

According to the Aufbau principle, the orbitals are filled in the following order:
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p, and so on.

Also the maximum number of electrons that can be accommodated in s, p, d & f orbitals are mentioned in the below table.

Orbitals	Maximum capacity of electrons [1]
s	2
p	6
d	10
f	14

Now let’s try to find the electron configuration of Chlorine by using the Aufbau principle.

Electron Configuration of Chlorine:

Follow the steps mentioned below to get the electron configuration of Chlorine.

• To write the electron configuration of chlorine, we should first know the total number of electrons present in a chlorine atom.
• The chlorine atom has a total of 17 electrons because its atomic number is 17 and it is a neutral atom. ^[2]
• Now we have to fill these 17 electrons in the atomic orbitals according to the Aufbau principle.
• According to the Aufbau principle, the electrons will be filled first in 1s orbital, then in 2s orbital, then in 2p orbital, and so on…
• So from the Aufbau principle, we can get the electron configuration of the chlorine atom as 1s² 2s² 2p⁶ 3s² 3p⁵. ^[3]

Now in this electron configuration of chlorine, we have to see the total number of electrons present in the highest energy level.

You can see in the electron configuration of chlorine (1s² 2s² 2p⁶ 3s² 3p⁵) that the highest energy level is 3. And the total number of electrons present in this energy level is 2 + 5 = 7.

So by knowing the electron configuration, we have found that the Chlorine has 7 valence electrons.

I hope you have understood the methods of finding the valence electrons in chlorine.

See more related topics for your practice;
Argon Valence Electrons
Gallium Valence Electrons
Germanium Valence Electrons
Arsenic Valence Electrons
Selenium Valence Electrons