Draw and Explain the Lewis Structure for NH3

The Lewis structure for NH₃ (ammonia) can be drawn by following these steps:

1. Count the total number of valence electrons: Nitrogen (N) has 5 valence electrons, and each hydrogen (H) has 1 valence electron. Since there are 3 hydrogen atoms, the total number of valence electrons is 5 + (3 × 1) = 8.
2. Determine the central atom: In NH₃, nitrogen is the central atom because it is less electronegative than hydrogen and can form multiple bonds.
3. Draw the skeletal structure: Place the nitrogen atom in the center and the three hydrogen atoms around it.
4. Distribute the electrons: Start by placing a pair of electrons between the nitrogen and each hydrogen atom to form single bonds. This uses up 6 electrons (3 pairs).
5. Place the remaining electrons: The remaining 2 electrons are placed on the nitrogen atom as a lone pair.

The final Lewis structure for NH₃ looks like this:

    H
    |
H—N—H
    |
    :

Explanation: In the Lewis structure of NH₃, the nitrogen atom forms three single bonds with hydrogen atoms and has one lone pair of electrons. This lone pair gives ammonia its characteristic properties, such as its ability to act as a base by donating the lone pair to a proton (H⁺). The structure is trigonal pyramidal due to the lone pair repelling the bonding pairs, causing the hydrogen atoms to be pushed slightly closer together.