[oceanmd]

Based on Iron's position in periodic table, what charge would we expect it to have?

Iron is a transition metal, it's electron configuration is 2, 8, 14, 2. It uses electrons from d and s orbitals to bond with other elements. I guess it has 8 valence electrons (6 from 3d-orbital and 2 from 4s-orbital). It has oxidation charges: +2, +3, +4, +6

But what charge do we expect it to have based on its position in the table? Is it +2 because it is the outermost shell? Or is it +6 because it is in d block?

Please explain. Thank you   

[oceanmd]

I will try to answer my question.
When d-block elements form ions, the 4s electrons are lost first. The oxidation number we can predict from the periodic table is 2+ because Fe loses 2 electrons from 4s orbital first.

Is this correct? Thank you

[oceanmd]

I received my work back and 2+ is marked wrong. It is 3+ Can somebody explain why or post the link to the explanation. Thank you

[Mr Lead]

Your opinion about electronic configuration and atomic orbital order is correct but in my opinion is not the answer to your problem.

1-Why Iron is not +6? Why does not exist,for example, FeF8[/b][/b]?
From 8th to 12th group of the 4th period you never arrive to the maximum oxidation state for that group (example:you'll never find Fe,Co,Ni,Cu,Zn with oxidation state corrisponding to the number of their own group).This is explained by steric factors, indeed atomic ray is smaller going from left to right and high oxidation state are not well tolerated.
If you want a better explanation of trends of oxidation states you can read Frost diagram...tell me if you don't find them..I don't know if is possible posting links in this forum..sorry is my first post here.

2-Oxidation state of an element depends from many factors;Is well known that Fe3+ is the most stable form of Iron...but only because air oxygen easily oxidate Fe2+ to Fe3+..The most widespread form is Fe2O3 (rust) where Fe is +3.
If you let an iron salt like FeCl2 on openair, iron will be immediately oxidized to Fe3+.but you are in air..
In other conditions, where the pH is lower Fe2+ can exist stably too..
In the question,of your teacher I think, he/she should be more precise and say the kind of environment you talk..
but obviously if not specified..usual oxidation state of Fe is 3 in the common life.

[oceanmd]

Mr Lead,

I am glad you joined this forum, and thank you very much for taking time to explain. 

[Mr Lead]

Thank you.
I hope the answer about IRon is clear.

[oceanmd]

Mr Lead

If the question was " What is the most stable form of Iron?" Then the answer is Fe3+

But the question is "Based on Iron's position in periodic table, what charge of oxidation can be predicted"
My understanding is that based on iron's position, its charge cannot be predicted.

Thank you again for all your help