Question

If the radius of ground state hydrogen is 51 pm, find out the radius of 5th orbit of Li2+ ions. (closest integer)

Answer 1

The answer is $425$
$r_{H}=51pm$
$(r_{H}^{2+})_{5}= (r_{H})_{1}\times\frac{n^{2}}{Z}=51\times\frac{5^{2}}{3}=425pm$