Redox Reaction

• The term “oxidation” referred to reactions of substances with oxygen, while “reduction” involved the removal of oxygen. 
• Redox reaction doesn't necessarily involve oxygen.
• Oxidation-reduction reactions are those that involve the movement of electrons or electrons from one particle to another.
• Redox reactions are therefore made up of two half-processes that occur together: the losing of electrons or oxidation, and the gaining of electrons or reduction.​
• An oxidation number is a positive or negative number assigned to an atom to indicate its degree of oxidation or reduction.
• In binary ionic compounds, the oxidation numbers of the atoms equal their ionic charges. 
• The oxidation number of hydrogen in a compound is +1, except in metal hydrides, such as NaH, where it is –1.​
• The oxidation number of oxygen in a compound is –2, except in peroxides, such as H2O2, where it is –1, and in compounds with the more electronegative fluorine, where it is positive.​
• The oxidation number of an atom in uncombined (elemental) form is 0.
• For any neutral compound, the sum of the oxidation numbers of the atoms in the compound must equal 0.
• For a polyatomic ion, the sum of the oxidation numbers must equal the ionic charge of the ion.