You write down the half equation.
Sn^2+ ==> Sn^4+.
The charge on the left is 2+. On the right it is 4+ . You add 2e (each with a - charge to the right so the charge balances.
That is one of the simple ones and the Fe is the same way. Others may be a little more complicated but you follow the rules. Here is a site that gives the rules along with a lot of other stuff about redox. Read this and you will be able to do all of them.
http://www.chemteam.info/Redox/Redox.html
I haven't learned half reactions for oxidation and reduction so please teach me by leading me from step to step....
I don't get this..
Sn2+ +2Fe3+---> Sn4+ +2Fe2+
The answer key says
Oxidation: Sn2+--->Sn4+ +2e-
Reduction: 2Fe3+ + 2e----->2Fe2+
**where did the 2 electrons come from???
1 answer