1.7 oxidation,reduction and redox reactions

• Reduction and oxidation involve the transfer of electrons.
• The acronym OIL RIG stands for oxidation is the loss of electrons, reduction is the gain of electrons.
• In a redox reaction, one element is oxidized and another element is reduced.
• Calcium is being oxidized in the reaction because it's losing electrons, forming Ca 2+.
• Oxygen is being reduced in the reaction as it's gaining electrons, forming OH-.
• Calcium combined with oxygen forms Ca 2+.
• When calcium combines with oxygen, it forms Ca 2+ because it's losing electrons.
• When oxygen combines with calcium, it forms OH- because it's gaining electrons.
• Group two elements are always oxidation state of plus two.
• The most electronegative element takes priority in terms of oxidation state.
• Oxygen is oxidation state of minus two except in peroxide where it's minus one and in Oh F - where it's plus two.
• Uncombined elements always have an oxidation number of zero.
• Fluorine is always oxidation state of minus one.
• Group one elements are always oxidation state of plus one.
• Group three elements are always oxidation state of plus three.
• Hydrogen is always oxidation state of plus one except in hydrides where it's minus one.
• Each element can be assigned an oxidation number, which depends on a set of rules.
• Ions have an oxidation number that is the same as the charge on the ion.
• Reducing agents lose electrons and oxidize themselves.
• In the reaction, calcium is the reducing agent as it's losing electrons.
• Oxidizing agents gain electrons and are themselves reduced.
• In the reaction, oxygen is the oxidizing agent as it's accepting electrons.
• In NaCl, sodium is +1 and chlorine is -1, so the reaction is oxidation.
• Peroxide has an oxidation number of -1 because it contains one oxygen atom.
• Oxygen is -2 in peroxide because it has four hydrogens attached.
• In Fe3O4, iron is +3 because the oxidation number of oxygen is -2.
• In Fe2O3, both ions are +6 because the oxidation number of oxygen is -2.
• In VO2, vanadium is +4 because the oxidation number of oxygen is -2.
• In FeO, iron is +3 because the oxidation number of oxygen is -2.
• In V2O3, vanadium is +4 because the oxidation number of oxygen is -2.
• In SO2, sulfur is +6 because it is the most electronegative element.
• In V2O5, vanadium is +5 because the oxidation number of oxygen is -2.
• In SO4 2-, sulfur is +6 because it has a charge of -2.
• In H2SO4, oxygen is -2 because it is the most electronegative element.
• In the reaction MnO4- MN2+, the species before and after are written down, and the atoms apart from oxygen and hydrogen are balanced.
• In a half equation, any atoms apart from oxygen and hydrogen are balanced, oxygens are balanced with water, hydrogens are balanced with H+ ions, and charges are balanced with electrons.
• Sodium ethoxide increases in oxidation number and chlorine decreases in oxidation number, resulting in a reduction.
• The total charge on the reaction MnO4- MN2+ must be zero, and this is achieved by balancing electrons.
• The oxygens in the reaction MnO4- MN2+ are balanced with water, and the hydrogens are balanced with H+ ions.
• The total charge on a half equation must be zero, and this is achieved by balancing electrons.