00:01
Hi there.
00:02
In this question, we are determining some oxidation numbers.
00:05
So in letter a, we need the oxidation number of each element in this ion.
00:14
Okay, so using some of the rules for assigning oxidation numbers, the first one we're going to use is that oxygen has an oxidation number of negative 2, unless it is in a peroxide.
00:32
But this is not a peroxide, so oxygen is going to be negative 2.
00:35
The next one is, the next rule that we need to use is that in an ion, the sum of the oxidation numbers must equal the charge of the ion.
01:02
Okay, so we see here that we have four oxygen that are negative two each.
01:08
And the total ion charge is a single negative one.
01:13
That means the manganese, which we'll assign the letter x here, we can solve for.
01:18
So x minus 8 equals negative 1.
01:22
Add 8 to each side, and x equals positive 7.
01:27
All right, so our manganese is positive 7.
01:32
Okay, so the mn is positive 7, and the oxygen has an oxidation number of negative 2...