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Oxidation states of vanadium. AH Chemistry, Unit 1(c). Aims. Illustrate the presence of several oxidation states for vanadium Show how it is possible to change from one oxidation state to another. What are “oxidation states”?.
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Oxidation states of vanadium AH Chemistry, Unit 1(c)
Aims • Illustrate the presence of several oxidation states for vanadium • Show how it is possible to change from one oxidation state to another
What are “oxidation states”? • The actual charge of an atom if the atom is a monatomic ion, or the hypothetical charge assigned to an atom by certain rules
Rules • Elements are 0 • Atoms of monatomic ions have charge of ion • O is -2 in most compounds • H is +1 in most compounds • F is -1 in all compounds • Sum of numbers in a compound is 0; in a polyatomic ion is charge of ion
Example • Oxidation number of Cl in: • HClO4 (perchloric acid) • ClO3- (chlorate ion)
The significance of transition metals • Transition metals exhibit variable oxidation states of differing stability • A change in oxidation state can bring about a change in colour
Oxidation and reduction • Oxidation can be considered as an increase in oxidation number • Reduction can be considered as a decrease in oxidation number • Compounds with metals in a high oxidation state tend to be oxidising agents whereas compounds with metals in a low oxidation state are often reducing agents