S in Na₂S₂O₃
S is +2 in sodium thiosulphate, an average.
Oxidation number
Type a formula or an ion: K2Cr2O7, Cr2O7 2-, MnO4-, NH4+ or K4[Fe(CN)6]. Put a known ion in brackets when two elements are unknown. Pick an element to solve for it.
S+2average
The two S atoms in S₂O₃²⁻ are bonded differently, so their own values differ. The rules give the average, +2.
- Na is an alkali metal: +1 in its compounds.
- Oxygen is −2 in most compounds.
- The oxidation numbers add up to the charge, 0: 2(+1) + 3(−2) + 2x = 0.
- 2x = +4, so x = +2.
How to find it
- Na is an alkali metal: +1 in its compounds.
- Oxygen is −2 in most compounds.
- The oxidation numbers add up to the charge, 0: 2(+1) + 3(−2) + 2x = 0.
- 2x = +4, so x = +2.
The two S atoms in S₂O₃²⁻ are bonded differently, so their own values differ. The rules give the average, +2.
All the oxidation numbers in Na₂S₂O₃
- Na +12 atoms, alkali metal
- O −23 atoms, oxygen
- S +22 atoms, sum rule
S in Na₂S₂O₃: quick answers
What is the oxidation number of S in Na₂S₂O₃?
S in Na₂S₂O₃ (sodium thiosulphate) is +2, an average over its atoms. The two S atoms in S₂O₃²⁻ are bonded differently, so their own values differ. The rules give the average, +2.
How do you find the oxidation number of S in Na₂S₂O₃?
Na is an alkali metal: +1 in its compounds. Oxygen is −2 in most compounds. The oxidation numbers add up to the charge, 0: 2(+1) + 3(−2) + 2x = 0. 2x = +4, so x = +2.
What are the oxidation numbers of the other atoms in Na₂S₂O₃?
Na +1, O −2. Together with S at +2 they add up to the charge of the compound, 0.