Helium is having two unit charges in the nucleus.
A hydrogen-like ion is an ion containing only one electron. The energies of the electron in a hydrogen-like ion are given by
E=-(2.18×10-18J) (Z2) (1/n2)
n is the principle of quantum number
Z is the atom number of the element
I.E = 8.72×10−21×6.02×1023 = 5250xkJ/mol