oxidation state of 2MnO4?

Question

Im confused about what to do with the 2 in front of Mn & my sheet says that Mn has a state of +7? How was that found?

Answer 1

First of all, MnO4 has a -1 charge as it is the permanganate ion MnO₄^-).. You ignore the 2 in front of the MnO₄^- because that just tells you how many moles or molecules etc. of MnO₄^- you have. The oxidation state doesn't change whether you have 1, 10 or 100 moles. The way you determine the oxidation number of Mn is as follows:

The oxidation number for O is 2- and there are 4 of them, for a total of -8.

Since the charge on the entire MnO4 molecule is -1, that means the Mn must have a charge/oxidation number of +7. So, that's how you get the answer.