Structure of Atom

Potential energy of H-atom is taken as zero when electron and nucleus are at infinite distance (given).
∴ P.E. of a H-atom with electron in its ground state
= – 27.2 eV (from Bohr's Model)
At internuclear distance ' d0 ; electron-electron repulsion and nucleus-nucleus repulsion are absent.
∴ P.E. of two H-atom = – 2 × 27.2 eV = – 54.4 eV
=−5242.42kJ∕mol