Summary:
- Transition elements are the elements that are found in Groups 3-12 (old groups IIA-IIB) on the periodic table.
- The term refers to the fact that the d sublevel, which is in the process of being filled, is in a lower principal energy level than the sublevel filled before it.
- Because of this unique filling order, the transition elements are often referred to as “d-block” elements.
- As a group, they display typical metallic properties and are less reactive than the metals in Groups 1 and 2.