Identify the species in which the central atom has an oxidation state of $+6$.

What is the oxidation state of oxygen in $O_2^{2-}$ ion?

Calculate the oxidation number of sulfur,chromium,and nitrogen in $H_2SO_5$,$Cr_2O_7^{2-}$,and $NO_3^-$. Suggest the structures of these compounds and explain the fallacy in the direct calculation of the oxidation number for $H_2SO_5$.

What is the oxidation number of chlorine in $ClO_3^-$?

The oxidation number and the electronic configuration of sulphur in $H_2SO_4$ is

In which one of the following changes is there a transfer of five electrons?