Group 3 element

A group 3 element is a group in the periodic table of chemical elements. 
Is one of the 18 groups in periodic table of elements. In this group are:
The first two elements of this group are known, while the other two do not know whether it was lutetium and lawrencium or lanthanum and actinium.
This group is called the I - {IIIB} - group of chemical elements.