Lewis Beverage cup structure in the case of ammonia is a representation of the valence electrons surrounding the N atom. The dot point structure for NH3 reveals that the N atom unites a solitary pair of electrons with each of the three hydrogen atoms, resulting in a complete of three connected pairs of electrons. The ammonia molecule takes a trigonal pyramidal shape because of the arrangement of the outer electrons according to its Electron pair dot arrangement. In the dot symbol representation of ammonia, the N atom is encircled by three dots, each representing a pair of shared electrons with a H atom.