Question

According to the VSEPR model, the predicted molecular geometry of ammonia, NH₃, is:

1) linear
2) trigonal planar
3) tetrahedral
4) trigonal pyramidal

Answer 1

The molecular geometry of NH3 is trigonal pyramidal due to the presence of a lone pair on the central nitrogen atom. The H-N-H bond angles in NH3 are slightly smaller than the ideal 109.5° angle in a regular tetrahedron.

Step-by-step explanation:

The molecular geometry of NH3 is trigonal pyramidal. In the ammonia molecule, the three hydrogen atoms attached to the central nitrogen form a three-dimensional trigonal pyramid. This is because one of the electron pairs is a lone pair instead of a bonding pair, which influences the shape. The ideal bond angles in a trigonal pyramid are based on the tetrahedral electron pair geometry, but there are slight deviations due to the repulsion between lone pairs and bonding pairs. The H-N-H bond angles in NH3 are slightly smaller than the ideal 109.5° angle in a regular tetrahedron.