Answer:
The d-block and transition metal are not interchangeable terms because the d-block elements are a subset of the transition metal elements. The transition metals are defined as the elements that have partially filled d orbitals, which includes the d-block elements as well as other elements that have partially filled d orbitals in other blocks, such as lanthanides and actinides. Therefore, while all d-block elements are transition metals, not all transition metals are d-block elements.