In an ammonia molecule (NH3), the nitrogen atom shares its valence electrons with the three hydrogen atoms, forming covalent bonds. These covalent bonds are formed by the overlap of atomic orbitals, resulting in the sharing of electrons between the atoms.

In contrast, ionic compounds are formed by the complete transfer of electrons from one atom to another, resulting in the formation of positively charged ions (cations) and negatively charged ions (anions). Ammonia does not exhibit this type of electron transfer, as the atoms share electrons rather than transferring them completely.