Transition metals consist of elements from the d-block found between the group IIa and the group IIb elements of the periodic table. A transition metal is an element that forms one or more stable ions which have incompletely filled d sub-orbitals. While these transition metals contain at most two electrons in their outer shell, they are called d-block elements because their next highest energy shell has incompletely filled d sub-orbitals.
Contributors and Attributions
Zane Sterkewolf (UCD)