Question
The ground state energy of hydrogen atom is -13.6 eV. When its electron is in the first excited state, its excitation energy is
3.4 eV
6.8 eV
10.2 eV
zero
Solution
C.
10.2 eV
Excitation energy is defined as the energy required to take the electron from ground level orbit to any higher order orbit (ie, n = 2,3,4...)
Given, ground state energy of hydrogen atom
E1 = - 13.6/(2)2 eV
Energy of electron in first excited state (ie, n = 2)
E2 = - 13.6/ (2)2 eV
Therefore, excitation energy
ΔE = E2-E1
=(-13.6/4) - (-13.6)
= - 3.4 + 13.6 = 10.2 eV
