Answer: In metallic bonds, the mobile electrons surrounding the positive ions are called <u><em>dipole</em></u>.
The correct option is D.
The hydrogen atoms that are attached to the nitrogen atom in the ammonia molecule are capable of forming hydrogen bond. The hydrogen bond that exist in the ammonia molecule is the reason why it shows higher boiling point compare to the other hydrides. Hydrogen bond occur in ammonia because ammonia is one of the most electronegative elements.
The last set which is n=4 l=3 m=3 is a valid set
