Ionization energy of is 19.6×10−18 J atom−1. The energy of the first stationary state n = 1 of Li2+ is
IHe+ILi2+=Z21Z22 19.6×10−18ILi2+=49 ILi2+=94×19.6×10−18=44.1×10−18=4.41×10−17 J atom−1
Ionisation energy of He+ is 19.6×10-18 J atom-1. The energy of the first stationary state(n=1) of Li2+ is: