The Lewis structure of NH3 (ammonia) consists of a nitrogen atom at the center with three hydrogen atoms bonded to it. Nitrogen has five valence electrons, and each hydrogen atom has one valence electron. In the Lewis structure, nitrogen forms three single covalent bonds with the hydrogen atoms, using three of its valence electrons. The remaining two valence electrons on nitrogen form a lone pair. This lone pair gives NH3 its characteristic properties, such as its ability to act as a base. The structure can be represented as follows:
H
|
H—N—H
|
H
In this structure, the nitrogen atom is surrounded by four electron pairs (three bonding pairs and one lone pair), giving it a tetrahedral electron geometry. However, due to the lone pair, the molecular geometry is trigonal pyramidal.