Final answer:
An NH3 (ammonia) molecule contains polar bonds due to the electronegativity difference between nitrogen and hydrogen atoms, creating a dipole moment. Its trigonal pyramidal molecular geometry with a lone pair on nitrogen enhances its polarity. In an electric field, NH3 aligns according to the direction of its dipole moment.
Step-by-step explanation:
Yes, an NH3 (ammonia) molecule contains polar bonds because there is a difference in electronegativity between the nitrogen (N) and hydrogen (H) atoms. The nitrogen atom is more electronegative than the hydrogen atoms, meaning it attracts the bonded electron pair more strongly. This uneven distribution of electron density creates a dipole moment with a partial negative charge on the nitrogen atom and partial positive charges on the hydrogen atoms.
The molecular geometry of NH3 is described as trigonal pyramidal, with the nitrogen atom at the apex and the three hydrogen atoms at the corners of the base. This geometry is a result of the four electron groups around the central nitrogen atom—three of which are bonded to hydrogen atoms and the fourth being a lone pair. The presence of the lone pair contributes to the polarity of the molecule as it affects the distribution of electron density and the geometry of the molecule, making it asymmetrical.
Polar molecules like NH3 experience alignment in an electric field due to their dipole moment. The field will affect the orientation of the molecule, aligning the negative and positive ends in opposite directions corresponding to the direction of the field. This behavior underlines the property of dipole-dipole interactions seen in polar substances.