key term - NH3

Definition

NH3, commonly known as ammonia, is a colorless gas with a pungent smell, consisting of one nitrogen atom and three hydrogen atoms. In molecular orbital theory, NH3 is an important example of a molecule that exhibits hybridization and the formation of molecular orbitals, which helps to explain its geometry and bonding characteristics.

5 Must Know Facts For Your Next Test

1. NH3 has a trigonal pyramidal molecular shape due to the presence of a lone pair on the nitrogen atom, resulting in bond angles of approximately 107 degrees.
2. The nitrogen atom in NH3 undergoes sp³ hybridization, combining one s orbital and three p orbitals to form four equivalent hybrid orbitals.
3. Ammonia is a polar molecule because of the difference in electronegativity between nitrogen and hydrogen, leading to a dipole moment.
4. NH3 can act as both a Lewis base and a Brønsted-Lowry base, meaning it can donate an electron pair or accept protons in chemical reactions.
5. In molecular orbital theory, NH3 has bonding molecular orbitals formed from the overlap of nitrogen's sp³ hybrid orbitals with hydrogen's 1s orbitals.

Review Questions

• How does hybridization explain the bonding in NH3, and what is the significance of its molecular shape?
  • In NH3, the nitrogen atom undergoes sp³ hybridization to form four equivalent hybrid orbitals. Three of these hybrid orbitals form sigma bonds with hydrogen atoms, while the fourth contains a lone pair of electrons. This arrangement leads to a trigonal pyramidal molecular shape, which is crucial for understanding its reactivity and polarity, as it affects the bond angles and overall dipole moment of the molecule.
• Discuss how molecular orbital theory provides insights into the bonding characteristics and stability of NH3.
  • Molecular orbital theory reveals that in NH3, bonding occurs through the formation of molecular orbitals from the combination of atomic orbitals. The nitrogen atom's sp³ hybrid orbitals overlap with hydrogen's 1s orbitals to create bonding molecular orbitals that enhance stability. The presence of a lone pair on nitrogen contributes to its trigonal pyramidal shape and impacts its reactivity as a Lewis base.
• Evaluate the implications of NH3's polarity and hybridization on its interactions with other molecules in terms of solubility and reactivity.
  • The polarity of NH3 results from its bent molecular shape and electronegativity difference between nitrogen and hydrogen. This polarity allows ammonia to form hydrogen bonds with water molecules, leading to its high solubility in water. Additionally, due to its ability to donate lone pair electrons, NH3 is reactive in acid-base reactions. These properties are significant in biological systems and industrial applications, affecting how ammonia interacts with other substances.

Related terms

Hybridization:

The concept of hybridization describes the mixing of atomic orbitals to form new hybrid orbitals, which are used for bonding in molecules.

Molecular Geometry: Molecular geometry refers to the three-dimensional arrangement of atoms in a molecule, which can significantly affect the molecule's physical and chemical properties.

Bonding Orbitals: Bonding orbitals are molecular orbitals formed by the constructive interference of atomic orbitals, leading to an increased electron density between bonded nuclei.