What is the oxidation number of Mn in `KMnO_(4) and S` in `Na_(2)S_(2)O_(3)`?

Explanation

Let the Ox. No. of Mn in `KMnO_(4)` be x.
We know that, Ox. No. of K=+1
Ox.no. of O=-2
So, Ox no. K+Ox. No. Mn+4(Ox.no.O)=0
or `+1 +x +x4(-2)=0`
`+1 +x -8=0`
Or, x=+8-1=7
Hence, Ox. No of Mn in `KMnO_(4) is +7`
Similarly, for S in `Na_(2)S_(2)O_(3)`,
`2("Ox.no. Na")+2("Ox.no.S")+3("Ox.no.O")=0`
`2xx(+1)+2x+3(-2)=0`
x=+2
Hence, Ox. no. of S in `Na_(2)S_(2)O_(3)=+2`