Find the energy relased (in junles) when a doubly ionised helium `(He^(2+))` taken up two electron in form a helium atom in the ground state .The first ionisation energy of a helium atom is `3.4 xx 10^(-19) J`

Explanation

`IE`= ionisation energy of He
`IE_(1) = 3.4 xx 10^(-19) J`
`IE_(2) = IE `of `He^(o+)"ion" = 2.17 xx 10^(-18) xx (4) = 8.68 xx 10^(-18) J`
Total energy released
`IE_(1) + IE_(2) = (3.4 xx 10^(-19) + 8.68 xx 10^(-18))J = 90.2 xx 10^(-19) = 9.02 xx 10^(-18) J`