chemistry
posted by Lisa on .
calculate the energy of a photon emitted when an electron in a hydrogen atom undergoes a transition from
n=5 to n=1
how do I do this?

E = 2.180E18 J*(1/1^2  1/5^2)

I think I am doing something wrong.
I keep coming up with 8.72x10^17 and it is telling me I am wrong.
I know D E=2.18x10^18 x (1/1^21/5^2) 
i think I am not doing this part right
(1/n5^2  1/n1^2) 
2.0928 x 10(to the power of 18)