Question

Radius of 3rd orbit if lithium 2nd ion

Answer 1

$radius = 0.529 \times {n }^{2} \div z$
the formula gives radius in amstrongs
n=3 z=3
0.529×3
1.587 ×10^-10m

Answer 2

radius = 0.529 × n^2/z
= 0.529 × 3^2 /3
=1.587 A°