The energy different between the first two levels of hydrogen atom is `10.2eV`. What is the corresponding energy difference for a single ionized helium atom?

Options

A. `10.2eV`
B. `20.4eV`
C. `40.8eV`
D. `81.6eV`

Answer

C

Explanation

`E_(n)=13.6Z^(2)/n^(2)`
` DeltaE_(H)=(13.6(1)^(2))/(1)^(2)-(13.6(1)^(2))/((2)^(2))=10.2eV`
` DeltaE_(He)=(13.6(2)^(2))/((1)^(2))-(13.6(2)^(2))/(2)=40.8eV`