Advanced Placement (AP) Chemistry Practice Exam

The correct identification of hybridization and electron pair geometry for a molecule with six electron pairs and no lone pairs is indeed sp³d² hybridization. In this case, the presence of six electron pairs indicates that the molecular shape conforms to an octahedral geometry, which requires a specific arrangement of hybrid orbitals to accommodate these electron pairs.

During hybridization, the s and p orbitals mix alongside one of the d orbitals to form a total of six equivalent sp³d² hybrid orbitals. This specific hybridization allows the molecule to maintain optimal spatial distribution, minimizing electron pair repulsion, which is essential according to VSEPR theory. The electrons in these hybrid orbitals are arranged around the central atom in an octahedral shape, with bond angles of 90 degrees.

In contrast, options that suggest sp³, sp², or sp hybridization imply fewer electron pairs and bond arrangements that are incompatible with having six electron pairs. For instance, sp³ corresponds to four pairs (tetrahedral geometry), sp² corresponds to three pairs (trigonal planar geometry), and sp pertains to two pairs (linear geometry). Hence, sp³d² is the only option that accurately reflects both the number of electron pairs present and