It would be a positive 2. Since oxygen is more electronegative than hydrogen, therefore oxidation no. The oxidation number of fluorine is always -1 but the oxidation number of chlorine differs in different compounds. So if it is oxygen by itself (e.g., O2) then the oxidation number/state is 0. $\ce{CO2,CO}$ The sum of the oxidation numbers in a monatomic ion is equal to the overall charge of that ion. But it has an oxidation state of positive 2. For ClO4- the overall oxidation state must be -1 and the four oxygens together make -8 and … The concept of oxidation state simply works on concept of electronegativity.The more electronegative atom acquire a negative charge while less electronegative atom acquire a positive charge. Eg. O = -2 in most compounds. The oxidation state for oxygen, it's giving up these electrons. The oxidation number of any atom in its elemental form is 0. Zero. It is zero for nitrogen N2 gas, Br2, H2 essentially all nonmetal molecules of the same element (S8) or pure metals like Na (s), Fe (s) and Au (s) (all metals) are in their standard states. In all the oxides,oxygen has an oxidation state of $-2$. Thus the oxidation state of a one-carbon fragment is unambiguous and defined by the number of C-H bonds that have been replaced by C-X bonds, where X = any electronegative element (see periodic table on previous page). V = +5 The resulting atom charges then represent the oxidation state for each atom. And that's just the convention. Using postulated rules. In its compounds the oxidation number of oxygen is -2. For O atom, the most common oxidation state is -2. S^"+6" Some knowledge in oxidation numbers and algebra is in order. For H atom, the most common oxidation state is +1. Substituting HSO_4^- with its oxidation state values we have: (+1) + x + [(-2) * (4)] = -1, where x = unknown (+1) + x + (-8) = -1 x + (-7) = -1 x = … Valency and oxidation states of oxygen. As we know that, the sum of the oxidation numbers of … At a temperature of below -189.2 оС, oxygen becomes a liquid of a light blue color, and at -218.35 оС it moves into a crystalline state. The sum of the oxidation numbers must equal the overall charge on the particle -- -3 in this case. V + 4(-2) = -3. The oxidation number of any free element is 0. Let the oxidation no. of hydrogen in H 2 O 2 will be +1. of oxygen in H 2 O 2 be x. We write the sign after the number. Oxidation Reduction reaction in terms of oxidation number Generally the oxidation state of oxygen is -2. The sum of oxidation numbers in a neutral compound is 0. But compounds like H 2 O 2 and Na 2 O 2, oxidation number of oxygen is -1. Depending on this hypothesis oxygen have 5 oxidation states. And we talk about oxidation states when we write this little superscript here. Replacing C-H bonds by C-Metal bonds is not a redox process. Oxygen usually has an oxidation state of -2 and overall oxidation state of an ion is equal to the charge on the ion. A C=O double bond is equivalent to two C-O … Oxygen, the thing that likes to oxidize other things, … Thus: For ClO- the overall oxidation state must be -1 and the oxygen is -2 and thus the Cl must be +1.