The ionization energy of He-atom in ground state may be — Atomic Structure Chemistry Question

💡 Solution & Explanation

The first ionization energy of He atom (1s^2) is experimentally ~24.6 eV. Due to inter-electronic repulsion it is less than 54.4 eV (the I.E. for He^+). Among the options, 27.0 eV is the closest approximation used in the book's context.