About Oxidation and Reduction

[albertlee]

My chem book tells me that

 

Oxidation = loosing electrons

 

Reduction = gaining electrons

 

 

I am really confused why those meanings are called like such...

 

 

what does loosing electrons have to do with "oxygen"?

and

What does gainning electrons have to do with "reducing something"??

gaining is obvious not reducing...

 

 

Any help?

 

Albert

[budullewraagh]

consider oxygen. it is the 2nd most electronegative element and is found in many oxidizing polyatomic anions. fluorine is something of a beast and scientists didn't work with it much at all for a long time because basically it killed anyone who tried to get good data on it. so, that leaves oxygen, a pleasant element. oxygen reduces, gaining electrons, and thus acts as an oxidizing agent, causing other atoms to oxidize and lose electrons.

 

with regard to the term "reduce," it doesn't really matter. it's the concepts that matter rather than the names

[Tetrahedrite]

I have a feeling the term "reduced" comes from a lowering of the absolute charge of the atom/ion. For example when I reduce Fe3+ to Fe2+ I am lowering the charge number.

Just a suggestion, I don't know if this is correct

[budullewraagh]

what about if you reduce, say, P- to P-3?

[Tetrahedrite]

what about if you reduce, say, P- to P-3?

You are still reducing the oxidation number aka -3 is lower than -1

[budullewraagh]

lowering of the absolute charge of the atom/ion.

the absolute value of -3 is greater than that of -1...

[Guest TriggerDunpo]

but he said absolute charge, not value, so that could mean the final charge or something like that too

 

I used the same line of thought that reducing meant lowering the charge

[Tetrahedrite]

Yes.... as above....I did not mean to imply the absolute value of the charge.

[Technologist]

Initially oxygen was the only known oxidizing agent therefore the term oxidation was coined.

 

Reduction is a gain in elections. Electrons have a negative charge. If a species gains more negative charges then its oxidation number decreases. Fe3+ will reduce to Fe2+. Its oxiation number decreases.

 

Oxidation is a loss of electrons. Electrons have a negative charge. Therefore losing electrons = a greater positive charge.

[budullewraagh]

Electrons have a positive charge

they actually carry a negative charge

[Tetrahedrite]

Out of all the topics I teach to first year students, redox reactions are what cause the most problems. I think the nomeclature is a big problem. Of particular concern to many students is that an oxidising agent is reduced and a reducing agent is oxidised! I even have to stop and think carefully sometimes!!

[budullewraagh]

yeah, redox seems to be more difficult to most, altho it wasnt hard for me at all last year:\

[HNO3]

Reduction comes from "reducing" a metal ore to the pure metal.

[Tetrahedrite]

Reduction comes from "reducing" a metal ore to the pure metal.

Yeah...come to think of it, that would make sense!

[budullewraagh]

haha i know. it really does indeed make sense. well done

[chadn]

Out of all the topics I teach to first year students, redox reactions are what cause the most problems. I think the nomeclature is a big problem. Of particular concern to many students is that an oxidising agent is reduced and a reducing agent is oxidised! I even have to stop and think carefully sometimes!!

 

I think the hard-part of redox reactions is not the concept of gaining and losing electrons, its balancing them. I absolutely despise balancing half reactions, because of all the rules that go along with adding H+ ions and everything.

[budullewraagh]

i have a problem with the whole "losing" and "gaining" electrons concept in many situations. example: HF is highly polar and considered ionic but it is strongly bonded. in the case of SiI4, the bonds are polar sure but electrons certainly are not gained by the iodine and lost by the silicon