Answer:
B. PF₃
Explanation:
The electron geometry of a molecule is determined by the number of electron groups around the central atom, including both the bonding pairs and lone pairs. The molecular geometry, on the other hand, describes the arrangement of only the bonding pairs of electrons around the central atom.
A molecule with tetrahedral electron geometry has four electron groups around the central atom, which are arranged in a tetrahedral shape. A molecule with trigonal pyramidal molecular geometry has three bonding pairs of electrons and one lone pair of electrons around the central atom, which results in a pyramid-like shape.
Out of the given options, PF₃ has a tetrahedral electron geometry and a trigonal pyramidal molecular geometry. The phosphorus atom in PF₃ has three bonding pairs and one lone pair of electrons, which gives it a trigonal pyramidal shape. The molecule has a tetrahedral electron geometry because there are four electron groups around the central phosphorus atom.
Therefore, the answer is B. PF₃.
