What is the oxidation number of sulfur in SO4-2?
Try 6.
http://www.chemteam.info/Redox/Redox-Rules.html
To determine the oxidation number of sulfur in SO4-2, we need to assign oxidation numbers to each element in the compound.
1. Start by assigning oxidation numbers to the more electronegative elements first, which are oxygen (-2 in most compounds) and fluorine (-1 in most compounds).
2. Since there are four oxygen atoms in SO4-2 and each has an oxidation number of -2, the total negative charge contributed by oxygen is -8 (-2 × 4).
3. The overall charge of the ion is -2, so the sum of the oxidation numbers must equal -2.
4. Let x be the oxidation number of sulfur. Multiply the oxidation number by the number of sulfur atoms to get the total oxidation number contributed by sulfur. Since there is only one sulfur atom in SO4-2, the total oxidation number contributed by sulfur is x.
5. Set up an equation to find the oxidation number of sulfur:
x + (-8) = -2
6. Simplify the equation:
x - 8 = -2
7. Solve for x by adding 8 to both sides of the equation:
x = -2 + 8
x = 6
Therefore, the oxidation number of sulfur in SO4-2 is +6.