How Do You Determine If Compounds Contain Ions and Their Charges?

[givemeknowledge]

Hey,

So I've got a homework question which is gradually transforming by brain into mashed potato!

Here it is..

Identify which of the following compounds contains ions and state the formal charges on the ions: NaCl, N2, MgO, AlCl3, and CO2.

Now, I'm not asking for someone to come in and give me the answer to all of them, I'm just after how I can find the answers, I just don't understand after a long time Googling..

I've had a crack and found that NaCl is ionic, but I just don't understand how to figure out the formal charge..

I'm at a loss, any help will be great - thank you!

 

[DrClaude]

Hint: octet rule-

By the way, please do not remove the homework template, but use it to set up your question.

 

[givemeknowledge]

Hint: octet rule-

By the way, please do not remove the homework template, but use it to set up your question.

I've read about the octet rule but just can't join the two together, FML.

Okay I won't in future, I'm very new here.

 

[DrClaude]

Take NaCl as an example. What do you need to do to Na and Cl so that both follow the octet rule?

 

[givemeknowledge]

Na needs to gain an electron (I think) and Cl needs to lose an electron to reach the nearest full shell

 

[givemeknowledge]

So would I be right in thinking...

If N2 is 2 nitrogen atoms, and both have a charge of 3- does that give it a formal charge of 6-?

One thing that's confusing me.. The question says "the following compounds" yet N2 is not a compound... hmm

 

[DrClaude]

Na needs to gain an electron (I think) and Cl needs to lose an electron to reach the nearest full shell

What is the electron configuration of Na and Cl?

If N2 is 2 nitrogen atoms, and both have a charge of 3- does that give it a formal charge of 6-?

Don't you have to determine if ir contains ions first?

One thing that's confusing me.. The question says "the following compounds" yet N2 is not a compound... hmm

What do you call a compound?

 

[givemeknowledge]

What is the electron configuration of Na and Cl?

Na - 1s^2 2s^2 2p^6 3s^1

Cl - 1s^2 2s^2 2p^6 3s^2 3p^5

Don't you have to determine if ir contains ions first?

Yeah I do!

What do you call a compound?

Something made up of more than one element's atoms?

 

[DrClaude]

So, for Na and Cl, what is the simplest way to fulfill the octet rule?

Does N₂ contain ions? Indeed, it is not strictly speaking a compound, but you can treat it as such for this question (actually, this gives you a hint as to whether it contains ions or not).

 

[Borek]

While N₂ is technically not a compound, it is still a molecule - so it can either be ionic, or not.