Imagine removing one electron from He4 and He3. Their energy levels, as worked out on the basis of Bohr model will be very close. Explain why.
When we remove one electron from the isotopes of Helium i.e. He4 and He3 then both these atoms have only one electron and can be considered as a hydrogen like atom also it’s nucleus is much more heavier than H-atom. So their energy levels, as worked out on the basis of Bohr model will be very close.