What is the Ionic Charge of Selenium (Se)? And Why?

The Ionic Charge of Selenium (Se) is 2-.

But the question is how can you find the ionic charge on Selenium (Se)?

Well there are 2 methods by which you can find the ionic charge of Selenium (Se).

Lets dive right into these methods one by one.

You can also refer to the below video from which you will learn to find charge of any ion.

Method 1: By looking at the ionic charge trends on periodic table

This is a very simple method to determine the ionic charge of the monatomic ions.

First of all, let’s look at the group-wise ionic charge trends on the periodic table.

You can see in the above periodic table that; 

• Elements of group 1 have 1+ ionic charge,

• Elements of group 2 have 2+ ionic charge,

(Exclude transition metals, because they have variable ionic charges)

• Elements of group 13 have 3+ ionic charge,

(Exclude group 14, because they can have 4+ or 4- ionic charges)

• Elements of group 15 have 3- ionic charge,

• Elements of group 16 have 2- ionic charge,

• Elements of group 17 have 1- ionic charge,

• Elements of group 18 have 0 ionic charge,

Now here our element is Selenium (Se) which lies in group 16 of the periodic table.

Hence the ionic charge of Selenium (Se) is 2-.

Note:
The blank area shown in the above periodic table are mostly the transition and post-transition elements.
They show variable ionic charge.
Hence we cannot find their ionic charge by simply looking at the periodic table.
In order to find the charge of these elements, we need to look at what it is bonded with.
For more information, read the example of finding the charge of Copper.

Okay so now let’s see another method to find the ionic charge of Selenium (Se).

Method 2: By using electron configuration

The electron configuration of Selenium is: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁴ or [Ar] 3d¹⁰ 4s² 4p⁴. ^[1]

You can see that the outermost orbit of Selenium has 6 electrons.

During the chemical reaction, selenium gains 2 more electrons and achieves the nearest noble gas configuration to become stable.

And as the Selenium (Se) gains 2 electrons, it forms Se^2- ion. 

Hence the ionic charge of Selenium (Se) is 2-.

I hope you have understood the reason behind the 2- charge of selenium. 

Check out some other related topics for your practice.

Related topics:
Charge of Vanadium (V)
Charge of Mercury (Hg)
Charge of Helium (He)
Charge of Gold (Au)
Charge of Cesium (Cs)