Given below are the pairs of group 13 elements showing their relation in terms of atomic radius.
$({\rm{B}} < {\rm{Al}}),({\rm{Al}} < {\rm{Ga}}),({\rm{Ga}} < {\rm{In}}){\rm{ and }}({\rm{In}} < {\rm{Tl}})$
Identify the elements present in the incorrect pair and in that pair find out the element (X) that has higher ionic radius $\left( {{{\rm{M}}^{3 + }}} \right)$ than the other one. The atomic number of the element (X) is