Dear Student,
Electronic configuration of the element in +2 oxidation state is [Ar] 3d1.
Thus the atomic number of the element should be = atomic number of Ar+1+2= 18+1+2=21
Thus the element is Scandium. It is a d block element
The electronic configuration of Sc= [Ar] 3d1 4s2. Here, n=4 therefore it belongs to the 4th period.
Group=total number of valence shell electrons=3
So, the element belongs to group 3, period 4.