Calaculate the ionization enthalpy of the hydrogen atom is its ground state.
Strategy: The ionization enthalpy `(Delta_(f)H)` is the minimum enegry required to take the electron from the ground state to the first unbound state so that the electron effectively escapes from the influence of the nucleus. This corresponds to exciting the electron from `m = 1` enegry state to `n = oo` enegry state.

Explanation

Make use to Eq. directly to calculate `Delta_(f)H`.
`Delta_(i)H = DeltaE = Z^(2)E_(1) ((1)/(n_(f)^(2))-(1)/(n_(i)^(2)))`
`= (1)^(2) (-13.6eV "atom"^(-1)) ((1)/(oo^(2))-(1)/(1^(1)))`
`= 13.6eV"atom"^(-1)`