Write Lewis structure of O_(2)^(-) ion and find out oxidation state of each oxygen atom? What is the average oxidation state of oxygen in this ion ?

Write Lewis structure of O_(2)^(-) ion and find out oxidation state of

1.	Write Lewis structure of O_(2)^(-) ion and find out oxidation state of each oxygen atom? What is the average oxidation state of oxygen in this ion ?
Answer» Solution :The Lewis STRUCTURE of `O_(2)^(-)` is `:overset(.)underset(..)(O)- underset(..)overset(..)(O):-. ` SINCE O atom CARRYING no charge has six electrons and hence its O.N. is zero but O atom carrying NEGATIVE charge has seven electrons and hence its O.N. is `-1` . THEREFORE , average O.N. of each O = 1/2 (0+1) = 1/2.