The radius of the 2nd orbit of Li2+ is x. The expected radius of the 3rd orbit of Be3+ is [2023]
(4)
R=0.529×n2Z
(rLi2+)n=2=0.529×(2)23=x
(rBe3+)n=3=0.529×(3)24
(rLi2+)n=2(rBe3+)n=3=r0×(2)23r0×(3)24
x(rBe3+)n=3=1627
(rBe3+)n=3=27x16