Charge of permanganate

[Shanzey]

How do we tell the charge of Mg in MgO4-? Is it because oxygen normally has a charge of -2, and the total compound is -1, thus causing us to determine that Mg has a charge of +7?

[PranaviKolla2B]

Yes, I believe your latter question demonstrates the correct method.

[Brittney Hun 2C]

Yes, since it has a charge of -1 that is the total charge you want to get at the end. Since oxygen has a -2 charge and there are 4 that makes it minus 8 so in order to get a net of -1 the remaining element would have a charge of +7.

[Daniel Chen 2L]

In general, you just add the charges up of all the elements in the compound and you should get the total charge.

[Keya Jonnalagadda 1A]

Yes, oxidation rules follow a hierarchy when determining oxidation numbers. For example, the oxidation number of oxygen in compounds is usually -2, which pertains to this question about permanganate. I believe a list of the rules is in our textbook, or online.

[Jeremy_Guiman2E]

Would we be able to determine Magnesium's charge first? Or is it always easier to start with elements like Oxygen first when determining molecular charges?