What is the Ionic Charge of Rubidium (Rb)? And Why?

The Ionic Charge of Rubidium (Rb) is 1+.

But the question is how can you find the ionic charge on Rubidium (Rb)?

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

Lets dive right into these methods one by one.

If you are a visual learner like me, then here is a short two minute video for you.

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 Rubidium (Rb) which lies in group 1 of the periodic table.

Hence the ionic charge of Rubidium (Rb) is 1+.

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 Rubidium (Rb).

Method 2: By using electron configuration

The electron configuration of Rubidium is: 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 5s¹ or [Kr] 5s¹. ^[1]

You can see that the outermost orbit of Rubidium has 1 electron.

During the chemical reaction, rubidium loses this 1 electron and achieves the nearest noble gas configuration to become stable.

And as the Rubidium (Rb) loses 1 electron, it forms Rb⁺ ion. 

Hence the ionic charge of Rubidium (Rb) is 1+.

I hope you have understood the reason behind the 1+ charge of rubidium. 

Check out some other related topics for your practice.

Related topics:
Charge on CN (Cyanide ion)
Charge of Selenium (Se)
Charge of Vanadium (V)
Charge of Mercury (Hg)
Charge of Helium (He)