Question

@satellite73
Did I get this problem right?

What is the oxidation number of sulfur in the S2O8^2- ion?

2s+8(-2)=-2
2s-16=-2
2s=14
s=7

Answer 1

@agent0smith
Did I get this problem right?

Answer 2

@mathstudent55

Did I get this problem right?

Answer 3

yes you are correct @badwolf1646

Whenever you have an ion the sum of the oxidation states equals the ion. so in this case we have -2, so the sum of oxidation states must equal -2.

we have 8 atoms of oxygen


so let's make an equation

\[2S+8O = -2 \]

we know the oxidation state of oxygen is -2

so let's re-arrange for sulfur

\[\frac{ -2-(8O) }{ 2 } = S\]

Now, we plug in our value for oxygen -2

\[\frac{ -2-8(-2) }{ 2 } = \frac{ -2+16 }{ 2 } = \frac{ 14 }{ 2 } = 7 \]

so each sulfur atom has an oxidation state of 7