To describe the characteristics of an ammonia ([tex]$NH_3$[/tex]) molecule, we can look into the bond polarities, molecular shape, and overall molecular polarity. Here are the steps to understand each of these characteristics:
1. Bond Polarities:
- Ammonia ([tex]$NH_3$[/tex]) is composed of nitrogen (N) and hydrogen (H) atoms.
- Nitrogen has a higher electronegativity compared to hydrogen. The electronegativity of nitrogen is approximately 3.0, while that of hydrogen is approximately 2.1.
- Because there is a significant difference in electronegativity between nitrogen and hydrogen, the bonds between N and H are polar. This means that the electrons in the N-H bonds are more attracted to the nitrogen atom, creating a partial negative charge on nitrogen and a partial positive charge on hydrogen.
2. Molecular Shape:
- To determine the shape of the [tex]$NH_3$[/tex] molecule, we need to consider the arrangement of its electron pairs.
- Nitrogen in [tex]$NH_3$[/tex] has one lone pair and forms three single bonds with hydrogen atoms.
- According to the VSEPR (Valence Shell Electron Pair Repulsion) theory, the electron pairs will arrange themselves to minimize repulsion. This results in a trigonal pyramidal geometry where the nitrogen atom is at the apex and the three hydrogen atoms form the base of the pyramid.
- Therefore, the molecular shape of [tex]$NH_3$[/tex] is trigonal pyramidal.
3. Overall Molecular Polarity:
- The shape of the [tex]$NH_3$[/tex] molecule is asymmetrical due to the lone pair on the nitrogen.
- Given the polar nature of the N-H bonds and the asymmetrical distribution of electrons, the dipoles do not cancel out.
- As a result, [tex]$NH_3$[/tex] has a net dipole moment and is a polar molecule overall.
Putting it all together, the characteristics of the ammonia ([tex]$NH_3$[/tex]) molecule are:
- The bond polarities are polar because of the difference in electronegativity between nitrogen and hydrogen.
- The molecular shape is trigonal pyramidal due to the lone pair on the nitrogen atom affecting the arrangement of the hydrogen atoms.
- The molecule is polar overall because of its asymmetrical shape and the presence of polar N-H bonds.
Thus, we can fill in the blanks as follows:
The bond polarities are polar, the molecular shape is trigonal pyramidal, and the molecule is polar.
