The order of ionisation potential between He+ ion and H-atom (both species are in gaseous state) is: — Periodic Table and Periodicity Chemistry Question

💡 Solution & Explanation

Step 1: Both He^+ and H are single-electron species. The energy of a single-electron species is given by the Bohr formula: E_n = -13.6 * (Z^2 / n^2) eV. Step 2: Calculate the energy required to remove the electron from the ground state (n=1). For Hydrogen (Z=1), I.P. = 13.6 eV. For He^+ (Z=2), I.P. = 13.6 * (2^2 / 1^2) = 54.4 eV. Step 3: Comparing the values, the ionization potential of He^+ (54.4 eV) is significantly greater than that of Hydrogen (13.6 eV).