Read the given passage and answer the questions that follow : The anomalous behaviour of oxygen, like other members of p-block present in second period is due to its small size and high electronegativity. One typical example of effects of small size and high electronegativity is the presence of strong hydrogen bonding in H_2O which is not found in H_2S. The absence of d-orbitals in oxygen limits its covalency to four and in practice, rarely exceeds two. On the other hand, in case of other elements of the group, the valence shells can be expanded and covalence exceeds four. How can we expand the valency shell in the case of elements lying lower in the group of oxygen ?

Read the given passage and answer the questions that follow : The anom

1.	Read the given passage and answer the questions that follow : The anomalous behaviour of oxygen, like other members of p-block present in second period is due to its small size and high electronegativity. One typical example of effects of small size and high electronegativity is the presence of strong hydrogen bonding in H_2O which is not found in H_2S. The absence of d-orbitals in oxygen limits its covalency to four and in practice, rarely exceeds two. On the other hand, in case of other elements of the group, the valence shells can be expanded and covalence exceeds four. How can we expand the valency shell in the case of elements lying lower in the group of oxygen ?
Answer» Solution :ELEMENTS lying lower in the group of oxygen contain d-orbitals. THEREFORE we can expand the VALENCE SHELL.