Answer:
BORON
Ionization energy decreases down the group and going from left to right the period,
Luckily you have the elements from the same group that is Group III A also called boron family,
The position of Elements in this group are
- Boron (B)
- Aluminium (Al)
- Gallium (Ga)
- Indium(In)
- Thallium
- Nihoium
so keeping rules in mind the first element in the group has highest I.E. that is boron
