Question

Explain the formation of the ammonia molecules.

Answer 1

Formation of Ammonia:

• The molecular formula of ammonia is ${\mathrm{NH}}_3$.
• Atomic number of$\mathrm{N}=7$, its electronic configuration is $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^3$ hence valence electron$=5$
• Atomic number of$\mathrm{H}$$=1$, its electronic configuration is $1{\mathrm{s}}^1$hence valence electron $=1$
• In nitrogen, there is one s and three p orbitals. Since the s orbital is completely occupied, hybridization will not occur there. The three p orbital has $3$ electrons.
• And according to Valence bond theory, an atomic bond between two atoms is created when incompletely filled atomic orbitals overlap. A hybrid orbital is created when the unpaired electrons are shared.
• As a result, the three s orbitals of three hydrogen atoms will hybridize with the three p orbital of nitrogen. It will generate three $\mathrm{N}-\mathrm{H}$ sigma bonds. Tetrahedral geometry and trigonal pyramidal shape both are formed.
• $1$s-orbital and $3$ p-orbitals hybridize and overlap with the s orbitals of a Hydrogen atom to produce ${\mathrm{sp}}^3$ hybridization when it shares electrons with Hydrogen atoms.
• The Hydrogen atoms are symmetrically positioned around the Nitrogen atom, which forms the base, and the two nonbonding electrons form the top, giving ${\mathrm{NH}}_3$ its trigonal pyramidal molecular shape.

Therefore, ammonia(${\mathrm{NH}}_3$) is ${\mathrm{sp}}^3$ hybridized with trigonal pyramidal geometry.