What is the oxidation no. of sulphur in na2s2o6

Oxidation state of sulfur S: +5.

Explanation

Known oxidation states:

Na: +1. Sodium Na is a main group metal. The oxidation state of Na in compounds should be positive and the same as its group number. The new IUPAC group number (1 ~ 16) of Na is 1. The oxidation state of Na should thus be +1.O: -2. Oxygen is the second most electronegative element on the periodic table. The oxidation state of oxygen is mostly -2 with a few exceptions: .

What the question is asking for:

The oxidation state of S can vary from compound to compound. Let the oxidation state of S in be .

The oxidation state of each atom in a compound should add up to zero.

There are two Na atoms in this formula. The oxidation state on each is +1. Add ;There are six O atoms in this formula. The oxidation state on each is -2. Add ;There are two S atoms in this formula. The oxidation state of each is assumed to be . Add .

Sum of oxidation states on each atom in :

.

Again, this value should equals to zero since is overall a neutral compound.

;

.

Thus the oxidation state of sulfur in should be +5.