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Forums
need a bit of help

need a bit of help

we knnow

Example: Write the half equation for the change MnO4-> Mn2+
1. Balance the change in O.N. with electrons MnO4- + 5e->Mn2+ Mn changes from +7 to +2
what i dont get is how its +7 to begin with

Reply 1

ElleCee

Each of the Oxygens in MnO4- is worth -2 so the Oxygens total are equal to -8, the oxidation numbers in MnO4- must add up to -1 (because it is a -1 ion) so therefore the Mn must be +7

Hope this helps :smile:

feel free to ask if you don't understand my explanation

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