American Chemical Society (ACS) Chemistry Practice Exam

The Dz2 orbital is characterized by its unique shape and orientation compared to other d orbitals. It has a distinctive "doughnut" or "double-lobe" structure surrounding the nucleus, with one lobe oriented along the z-axis. This configuration differentiates it from the other d orbitals, which either lie in the xy, yz, or xz planes or do not feature the same type of axial symmetry. The Dz2 orbital is specifically defined by its ability to accommodate electrons in a manner that emphasizes the contributions from the z-axis. In contrast, other d orbitals like Dy2 or Dx2y2 have different shapes and orientations. For instance, Dy2 is related to the y-axis and lacks the axial symmetry found in the Dz2. The same applies to Dxy, which is planar and does not possess the characteristics of the Dz2 orbital. Therefore, identifying the Dz2 orbital correctly requires an understanding of its unique shape and orientation, which distinctly sets it apart from the other listed configurations.