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Naming compounds


Rachel Maddiee

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Does this do a good job of naming the compound and explaining how I determined it?

Step 1
Cation: Fe+3
Anion: O-2

Step 2
Iron has two oxidation numbers Fe+2 and Fe+3
The element iron (a transition metal) has an electron configuration of [Ar] 3d6 4s2 with atomic number 26. It has two electrons in its 4s orbital and 6 electrons in its 4d orbital. When iron loses the two 4s electrons, it attains a valency of +2. It can lose one of the paired electrons from the 3d subshell (which provides a more stable configuration), and it attains a valency of +3.

Step 3 
Fe2O3 = iron(III) oxide 
 

A22791BD-1752-4C1F-A619-05897A0DE1F7.jpeg

Edited by Rachel Maddiee
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There doesn’t seem to be any reason to include the electronic configuration in your answer or to go through how iron can exist as iron(II) or iron(III). You simply need to determine the oxidation state from the molecular formula you are given. The reason the have that second step in the flow chart is because some elements like iron can have multiple oxidation states, which means that unlike elements like oxygen or hydrogen, you can’t immediately tell what it is without doing a little math first. It’s not asking you to explain how an element can get those states based on its configuration or even where the electrons go / come from, which is what you have done. 
 

What I would include is the math for how you determined that the iron in Fe2O3 is iron(III). You’ve written that it has a 3+ oxidation but not how you got to that point.

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22 minutes ago, Rachel Maddiee said:

Can you please give me a hint to what kind of explanation it should be?

Looking back on your question and the flow chart, I think I might be getting you to explain a more complex concept that you don't need to worry about in this instance. Your explanation in your OP is fine based purely on that. Have you been learning how to assign oxidation states? 

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29 minutes ago, Rachel Maddiee said:

Yes, this is part of my studies. I’m following the example in my book but I need to show my work along with it so I was having trouble with that. I wasn’t sure if my explanation was correct.

Okay. It's not totally clear to me if you also need to show how you worked out that the oxidation state of the iron was 3+ or if you can just take that as given. Most naming questions that I see will tell you the oxidation states if it's ambiguous. Since it's not explicitly stated here, maybe you do need to give working for that part as well. Regardless, this part in your original answer:

 

10 hours ago, Rachel Maddiee said:

The element iron (a transition metal) has an electron configuration of [Ar] 3d6 4s2 with atomic number 26. It has two electrons in its 4s orbital and 6 electrons in its 4d orbital. When iron loses the two 4s electrons, it attains a valency of +2. It can lose one of the paired electrons from the 3d subshell (which provides a more stable configuration), and it attains a valency of +3.

 

Is not really needed / relevant. 

If you do need to show how you figured out that it is Fe3+ and not Fe2+, how would you do that? You've said that it is Fe3+, which is right, but I'm not clear on exactly how you worked that out or if you just guessed / looked it up. Could you elaborate on this part? I can go through it if you don't know how. 

I should also ask how you have been shown to determine / calculate oxidation states of atoms in a compound. 

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Just now, Rachel Maddiee said:

Ferrous = iron(II) 
Ferric = iron(III)

But you weren't told if it was ferrous or ferric, just given the molecular formula. That is why I am not sure how you are expected to know that it is iron(III) without actually calculating it. Anyway, it doesn't seem to matter. Based on their solution, what you have written is fine, but I would get rid of all the electronic configuration stuff. 

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How you wrote it is fine, but as I said, I would remove some of the stuff about electronic configuration as I don't think it's needed. I have crossed out what you don't need below. You might just add a sentence saying that the iron in Fe2O3 is Fe3+

 

12 hours ago, Rachel Maddiee said:

Does this do a good job of naming the compound and explaining how I determined it?

Step 1
Cation: Fe+3
Anion: O-2

Step 2
Iron has two oxidation numbers Fe+2 and Fe+3
The element iron (a transition metal) has an electron configuration of [Ar] 3d6 4s2 with atomic number 26. It has two electrons in its 4s orbital and 6 electrons in its 4d orbital. When iron loses the two 4s electrons, it attains a valency of +2. It can lose one of the paired electrons from the 3d subshell (which provides a more stable configuration), and it attains a valency of +3.

Step 3 
Fe2O3 = iron(III) oxide 
 

 

Also, this is a side note, but I believe iron can also have a 6+ oxidation state. 

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Okay, but the stuff about electronic configuration doesn’t really do that. If you don’t have to go through the process of determining oxidation state, then it seems to be enough (based on the screen shot you sent of the ref page) to simply say that iron has several oxidation states, but exists as Fe3+ in Fe2O3. 

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Transition metals 
Fe2+ has the lower state than oxygen (Fe3+ has the higher state), so “Fe” becomes ferrous. The name of Fe2+O can also be written as ferrous oxide.
The terms “ferric” and “ferrous” are both use to refer to ions containing iron, since iron’s symbol is “Fe.”
Ferrous = iron(II) 
Ferric = iron(III)
Oxide = O-2 Anions always take the –ide suffix. 

Can i leave this?

Edited by Rachel Maddiee
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It doesn't really add anything to your answer. The ferric and ferrous stuff is kind of irrelevant here (you're not being asked about that nomenclature). 

To answer your previous question, I thought I had posted a link for you last night but I guess it didn't post. Have a look through this https://www.chemguide.co.uk/inorganic/redox/oxidnstates.html

I would highly recommend chemguide as a resource for all of your future questions before posting here. They are very thorough. 

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1 hour ago, Rachel Maddiee said:

How would I show the rules that were applied for naming cations and anions that helped me to determine the name?

The point of determining the oxidation state is really just so you can determine what number to put in brackets. In your case, so you know that it is iron(III) oxide and not iron(II) oxide. You've already shown how you got to the oxide part. 

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