Oxygen differs from the other elements of the group. Compounds of oxygen with metals are more ionic in nature and hydrogen bonding is more important for oxygen compounds. Oxygen is never more than divalent beacasue when it hs formed two covalent bonds, there are no low energy orbitals which can be used for form. further bonds. However, the elements S,Se,Te and Po have empty d- orbitals which may be used for bonding, and they can form four or six bonds by unpairing electrons. The higher oxidation states become less stable on decending the group. The bond between S and O, or Se and O, are much shorter than might be expected for a single bond owing to `rho pi - dpi` interaction between the p- orbital of oxygen and d- orbital of S or Se. Which of the following statemet is incorrect ?A. Oxo-anions of sulphur have little tendency to polymerise compared with the phosphates and silicates.B. In pyrosulphurous acid `(H_(2)S_(2O_(5))`, the oxidation states of both the sulphur atoms are not same, they are +V and +IIIC. Concentrated `HNO_(3)` oxidises both sulphur and selenium to `H_(2)SO_(4) (+VI) and H_(2)SeO_(4) (+VI)` respectivelyD. Most metal oxides are ionic and basic in nature while non-metallic oxides are usually covalent and acidic in nature