Calculate the energy required for the process
` He^(+)(g) to He^(2+) (g) + e^(-)`
The ionization energy for the H atom in the ground state is `2.18xx10^(-18) J "atom" ^(-1)`

Explanation

The second `IE` of He is the same as the `1 E` of `He^(o+)` and the Bohr's equation may be applied to the ground state of `He^(o+)`,
for which `Z=2` and `n=1`.
`IE` of `He^(o+)=(Z^(2)xx1E "of" H)/n^(2)`
`=(4xx2.18xx10^(-18))/1J "atom"^(-1)`
`=8.72xx10^(-18) J "atom"^(-1)`