A transition metal with a completely filled d-subshell and an empty s-subshell is expected to have low reactivity. This is because the completely filled d-subshell is stable and does not readily participate in chemical reactions. The empty s-subshell also means that there are no valence electrons available for bonding.In comparison, a transition metal with a partially filled d-subshell and an empty s-subshell is expected to have higher reactivity. This is because the partially filled d-subshell has unpaired electrons that can participate in chemical reactions and form bonds with other atoms. The presence of unpaired electrons in the d-subshell allows the transition metal to exhibit variable oxidation states, which contributes to its reactivity.Overall, a transition metal with a partially filled d-subshell and an empty s-subshell is more reactive than a transition metal with a completely filled d-subshell and an empty s-subshell.