The quantun mechanical treatment of the hydrogen atom gives the enrgy value:
`E_(n) = (-13.6)/(n^2) eV "atom"^(-1)`.
Use the expression to find `DeltaE` between n = 3 and n = 4.

Explanation

When `n = 3`
`E_3 = (-13.6)/(3^2) = (-13.6)/(9) = -1.51 eV "atom"^(-1)`
When `n = 4`
`E_4 = (-13.6)/(4^2) = (-13.6)/(16) = 0.85 eV "atom"^(-1)`
`DeltaE = E_(4) - E_(3)`
`= -0.85 - (-1.51) = +0.661 eV "atom"^(-1)`
`DeltaE = E_(4) - E_(3)`
`= -1.511 - (-0.85)`
`= -0.661 eV " atom"^(-1)`.