| A | B |
|---|
| oxidation number of an element is | zero |
| Oxidation number of sodium in sodium compounds is always | +1 |
| Oxidation number of potasium in ptassium compounds is always | +1 |
| chlorine in Cl2 - oxidation number is | 0 |
| Cl in NaCl oxidation number is | -1 |
| oxidation number of O in its compounds (not with F)is always | -2 |
| oxidation numbe rof F in its compounds is always | -1 |
| sum of oxidation numbers of elements ina compounds | 0 |
| oxidation number of Al in its compounds is always | +3 |
| oxidation number of H in its compounds (apart from with metals)is always | +1 |
| oxidation number of Mg in its compounds is always | +2 |
| oxidation number of Ca in its compounds is always | +2 |
| the oxidation number of an element in a simple ion is | the charge on the ion |
| the sum of the oxidation numbers in a oxoanion is | the sum of the oxidation numbers |
| in ClO(-) if O = -2 Cl is | +1 |
| in ClO3(-) if O = -2 Cl is | +5 |
| in ClO4(-) if O = -2 Cl is | +7 |
| oxidation is loss (of e) reduction is | gain in e |
| OIL... | RIG |
| Na --> Na(+) is | oxidation |
| Cl2 ---> Cl(-) | reduction |
| This is oxidation | Fe(2+) ---> Fe(3+) |
| This is reduction | Fe(3+) ---> Fe(2+) |
| In SO4(2-) the oxidation number of S | is ....... in SO4(2-) |
| The oxidation number of S is +4 ... | in SO2 |
| the oxidation number of S is -2 ... | in Na2S |
| If SO4(2-) changes to S(2-) | the S has gained 6e |
| If SO4(2-) changes to S(2-) S has been ... | reduced |
