The ionisation energy of He^(+) is 19.6xx10^(-18)"J atom"^(-1) Calculate the energy of first stationary state of Li^(2+) ion.

The ionisation energy of He^(+) is 19.6xx10^(-18)"J atom"^(-1) Calcula

1.	The ionisation energy of He^(+) is 19.6xx10^(-18)"J atom"^(-1) Calculate the energy of first stationary state of Li^(2+) ion.
Answer» Solution :Ionisation energy of hydrogen LIKE species = Ionisation energy of `H XXZ^(2)` `"I.E of "He^(+)="I.E of H"xx4,"I.E of "H=(1.9xx10^(-18))/(4)"______(1)"` `"I.E of "LI^(2+)="I.E of "Hxx9," I.E of H"=("I.E of "Li^(2+))/(9)"____(2)"` `"Equating (1) and (2) "("I.E of "Li^(2+))/(9)=(19.6xx10^(-18))/(4)` `"I.E of "Li^(2+)=(19.6xx10^(-18)xx9)/(4)` The energy of first stationary state of `Li^(2+)` `=(-19.6xx10^(-18)xx9)/(4)=-4.41xx10^(-17)"J atom"^(-1)`