How much energy is required to ionise a H atom if the electron occupies n = 5 orbit? Compare your answer with the ionization enthalpy of H atom (energy required to remove the electron from n =1 orbit).

Question 2.14: How much energy is required to ionise a H atom if the electron occupies n = 5 orbit?  Compare your answer with the ionization enthalpy of H atom (energy required to remove the electron from n =1 orbit).
Answer
The expression of energy is given by,

Where,
Z = atomic number of the atom
n = principal quantum number
For ionization from n₁ = 5 to


Hence, the energy required for ionization from n = 5 to n = is 8.72 × 10^-20 J.

Hence, less energy is required to ionize an electron in the 5^th orbital of hydrogen atom as compared to that in the ground state.
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