Question

which of the following does not have trigonal planar electron-pair geometry?select the correct answer below:bf3alcl3pcl3bh3

Answer 1

Phosphorus trichloride (PCl3) does not have a trigonal planar electron-pair geometry; it has a tetrahedral electron-pair geometry and a trigonal pyramidal molecular structure due to the presence of one lone pair of electrons on the phosphorus atom.

Step-by-step explanation:

The electron-pair geometry refers to the arrangement of electron regions around the central atom in a molecule. For a molecule to possess a trigonal planar electron-pair geometry, it must have three regions of high electron density and no lone pairs affecting the geometry. Boron trifluoride (BF3), boron trichloride (BCl3), and aluminium chloride (AlCl3) are compounds that demonstrate this geometry, as they all have three bonds and no lone pairs on the central atom. The B-Cl bonds, for example, lie in a plane with 120° angles between them.

On the other hand, phosphorus trichloride (PCl3) has a tetrahedral electron-pair geometry because, in addition to its three bonds, phosphorus has one lone pair of electrons. The molecular structure of PCl3, consequently, is trigonal pyramidal, not trigonal planar.

Therefore, the molecule that does not have a trigonal planar electron-pair geometry is PCl3.

Answer 2

PCL3 does not have trigonal planar electron-pair geometry because it has a tetrahedral electron-pair geometry with one lone pair on the central phosphorus atom.

Step-by-step explanation:

In evaluating which of the following does not have trigonal planar electron-pair geometry, we need to consider the arrangement of electron regions around the central atom and the presence of lone pairs. Compounds like BF3, AlCl3, and BH3 have no lone pairs on the central atom and are surrounded by three regions of electron density which result in a trigonal planar electron-pair geometry with 120° angles between them. However, PCL3 has a tetrahedral electron-pair geometry due to one lone pair on the phosphorus atom, making it the molecule that does not have a trigonal planar electron-pair geometry.