# Thread: Electron configuration and ion formation

1. ## Electron configuration and ion formation

Question:

Show (in terms of electron configurations of the atoms involved and the ions formed) how the following pairs of elements form ionic compounds. Deduce the formulae of the compounds formed:

c. Sodium and oxygen

So this is my working:

Na (2,8,1) O(2,6)

I can't see what will happen though. If Na transfers 1 electron, it won't share the electron configuration of a noble gas ie (2,8).

I doubt Oxygen can transfer 6 electrons to sodium and even if it is possible, Na wll only be (2,8,7) not (2,8,8).

So can it be deduced that these two elements cannot form ionic compounds? Thanks.

2. ## Re: Electron configuration and ion formation

You are assuming that there has to be a one to one ratio of oxygen to sodium. For simplicity, and I recommend you do this, just look at the valency of the element (essentially number of electrons in the outer shell). Sodium has one, so it has a valency of +1. Oxygen needs two more to complete its outer shell, so its valency is -2. Now valencies need to sum to zero for a compound so simple maths shows that two sodiums and one oxygen will lead to a valency of zero. Thus the ionic compound is Na2O-> sodium oxide

3. ## Re: Electron configuration and ion formation

Originally Posted by deswa
You are assuming that there has to be a one to one ratio of oxygen to sodium. For simplicity, and I recommend you do this, just look at the valency of the element (essentially number of electrons in the outer shell). Sodium has one, so it has a valency of +1. Oxygen needs two more to complete its outer shell, so its valency is -2. Now valencies need to sum to zero for a compound so simple maths shows that two sodiums and one oxygen will lead to a valency of zero. Thus the ionic compound is Na2O-> sodium oxide
Thanks a lot deswa

Great tip too!

4. ## Re: Electron configuration and ion formation

Didn't want to make another thread but I got stuck with this question:

I'm stuck between M and R, reason why I even considered M and R is because I'm assuming that the noble gases are on the far right, so they must gain electrons --> Leading to electronegativity. But other than that, I'm really not sure what else to consider. Perhaps a clue if possible?

5. ## Re: Electron configuration and ion formation

Originally Posted by Aysce
Didn't want to make another thread but I got stuck with this question:

I'm stuck between M and R, reason why I even considered M and R is because I'm assuming that the noble gases are on the far right, so they must gain electrons --> Leading to electronegativity. But other than that, I'm really not sure what else to consider. Perhaps a clue if possible?
M.

6. ## Re: Electron configuration and ion formation

Can you explain why you'd pick M over R though?

7. ## Re: Electron configuration and ion formation

Originally Posted by Aysce
Can you explain why you'd pick M over R though?
As you move down the rows, the number of electron shells increase.

So, M has a lower number of shells than R. The nucleus (and thus protons) are closer to the shells and the electrostatic attraction level in M is greater (i.e. more electronegative)

8. ## Re: Electron configuration and ion formation

Originally Posted by Amogh
As you move down the rows, the number of electron shells increase.

So, M has a lower number of shells than R. The nucleus (and thus protons) are closer to the shells and the electrostatic attraction level in M is greater (i.e. more electronegative)
Ah okay I understand.

Thanks for your help And to someth1ng as well.

9. ## Re: Electron configuration and ion formation

Out of curiosity, what textbook(s) are you using to learn this stuff?

10. ## Re: Electron configuration and ion formation

Originally Posted by deswa
Out of curiosity, what textbook(s) are you using to learn this stuff?
Conquering chemistry - Heard good things about this book but it's my only source atm. Any recommendations?

11. ## Re: Electron configuration and ion formation

Originally Posted by Aysce
Conquering chemistry - Heard good things about this book but it's my only source atm. Any recommendations?
That's a good textbook. Chemistry Contexts is also good.

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