Electron configuration and ion formation (1 Viewer)

[Aysce]

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.

 

[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

 

[Aysce]

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!

 

[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?

 

[someth1ng]

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.

 

[Aysce]

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

 

[Amogh]

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)

 

[Aysce]

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.

 

[deswa]

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

 

[Aysce]

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?

 

[someth1ng]

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.