(b) (i) Name two oxometal anions of the 3d series of the transition metals in which the metal exhibits the oxidation state equal to its group number.
(ii) What is the effect of increasing pH on a solution of `K_2Cr_2O_7`?
(iii) Why is `Cu^+` not stable in aqueous solution ?
(iv) Name a member of Lanthanoid series which is well-known to exhibit `+4` oxidation state.
(v) name two elements of 3d series which show anomalous electronic configuration.