Final answer:
The elements with a partially-filled d subshell in their neutral atom state are the transition metals, which are found in groups 3 through 12 on the periodic table. The correct option identifying these elements is C. In Transition Metals.
Step-by-step explanation:
When considering the elements which have a partially-filled d subshell in their neutral state, we must look at the general electronic configuration of the elements in different groups on the periodic table. Group 1 elements (alkali metals) have a full s orbital, Group 17 elements (halogens) typically have a filled p orbital with a missing electron, and Group 18 elements (noble gases) have completely filled p orbitals with no vacancies for additional electrons. Contrastingly, transition metals, typically located in groups 3 through 12 on the periodic table, are characterized by the presence of unfilled d orbitals. Scandium, for example, a transition metal, has an electron configuration of [Ar]3d¹ 4s², indicating that the d sublevel is in the process of being filled. The transition elements on the periodic table possess this property, involving a d sublevel which is not fully filled in their neutral atom state.
Based on this information and the provided reference material, the correct option which identifies the elements with a partially-filled d subshell is C. In Transition Metals. This fulfills the specifics of the question as transition metals have (or readily form) partially filled d orbitals.