Magnesium Valence Electrons (And How to Find them?)

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

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

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

Let’s discuss this in short.

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

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

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 Magnesium atom (Mg), you can use two methods.

Method 1: From the Periodic Table

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

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

From the above image, you can see that the Magnesium (Mg) is present in the group 2 of periodic table.
(Note: Group 2 is also called group 2A).

So, as the magnesium element is present in group 2, it has 2 valence electrons.

In this way, by knowing the position of magnesium 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 magnesium.

Method 2: From the Electron Configuration

If you want to find the valence electrons of magnesium 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 Magnesium by using the Aufbau principle.

Electron Configuration of Magnesium:

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

• To write the electron configuration of magnesium, we should first know the total number of electrons present in a magnesium atom.
• The magnesium atom has a total of 12 electrons because its atomic number is 12 and it is a neutral atom. ^[2]
• Now we have to fill these 12 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 in the magnesium atom, the first 2 electrons will be filled in s-orbital (because s-orbital can hold only 2 electrons).
• Similarly, the next 2 electrons of a magnesium atom will be filled in 2s orbital, next 6 electrons will be filled in 2p orbitals (because p-orbitals can hold a maximum of 6 electrons) and the remaining 2 electrons will be filled in 3s orbital.
• So the electron configuration of the magnesium atom is 1s² 2s² 2p⁶ 3s². ^[3]

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

You can see in the electron configuration of magnesium (1s² 2s² 2p⁶ 3s²) that the highest energy level is 3. And the total number of electrons present in this energy level is 2.

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

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

See more related topics for your practice;
Potassium Valence Electrons  
Calcium Valence Electrons
Rubidium Valence Electrons
Strontium Valence Electrons
Cesium Valence Electrons