Question

How much energy is emitted when an electron moves from the n=4 state of a hydrogen atom to the n=2 state?

Answer 1

I found: `DeltaE=4.09xx10^-19J`

Explanation:

I would use the energy of the electron in each state as:
`E_n=-(13.6eV)/n^2=-(2.18xx10^-18J)/n^2`
so we get:
`n=2`
`E_2=-(2.18xx10^-18J)/2^2=-5.45xx10^-19J`
`n=4`
`E_4=-(2.18xx10^-18J)/4^2=-1.36xx10^-19J`

`DeltaE=E_4-E_2=-1.36xx10^-19J+5.45xx10^-19J=4.09xx10^-19J`

Corresponding to a difference of `2.55eV`.