Ionization energy of He+ is 19.6×10−18J atom−1. The energy of the first stationary state of Li2+ is

E=−k×z2n2 I=k×z2n2 Iαz2n2 I1I2=z12n12×n22z22 19.6×10−18 JI2=49 I2=19.6×10−18×94J I2=−44.1×10−18 J