Helium Valence Electrons (And How to Find them?)

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

Awesome! You can see that helium has 2 valence electrons.

But how can you say that Helium has 2 valence electrons
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How can you find these valence electrons?

Let’s discuss this in short.

Helium has 2 valence electrons because there are 2 electrons present in the outermost shell of the Helium (He) atom.

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

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

How to find the Valence Electrons?

In order to find the valence electrons of Helium atom (He), you can find from its electron configuration.

But for that, 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 Helium by using the Aufbau principle.

Electron Configuration of Helium:

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

• To write the electron configuration of helium, we should first know the total number of electrons present in a helium atom.
• The helium atom has a total of 2 electrons because its atomic number is 2 and it is a neutral atom. ^[2]
• Now we have to fill these 2 electrons in the atomic orbitals according to the Aufbau principle.
• According to the Aufbau principle, the electrons will be filled first in 1s orbital.
• So in the helium atom, the 2 electrons will be filled in s-orbital.
• So the electron configuration of the helium atom is 1s². ^[3]

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

You can see in the electron configuration of helium (1s²) that the highest energy level is 1. And the total number of electrons present in this energy level is 2.

So by knowing the electron configuration, we have found that the Helium has 2 valence electrons.

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

See more related topics for your practice;
Lithium Valence Electrons
Beryllium Valence Electrons
Sodium Valence Electrons
Magnesium Valence Electrons
Potassium Valence Electrons