Final answer:
The energy required to ionize an excited hydrogen atom is a little less than 13.6 eV because the electron is already in a higher energy state than the ground state.
Step-by-step explanation:
For the ionization of an excited hydrogen atom, the required energy is less than that for an atom in the ground state. The energy needed to ionize a hydrogen atom from its ground state is 13.6 electron volts (eV), an experimentally verified value. However, the ionization energy for a hydrogen atom in an excited state, as given by the energy level formula En = -13.6 eV/n², where n is the principal quantum number, will be less because the electron is already at a higher energy level than the ground state. When the atom is excited to the fifth state (n = 6), ionization requires only 0.378 eV, which is 36 times less than from the ground state.
To ionize an excited hydrogen atom, the amount of energy required is a little less than 13.6 eV. If an electron is to be removed from the fourth energy state, we can calculate its ionization energy using the aforementioned formula, substituting n with the value 4, which would give us a different ionization energy requirement. Generally, if an atom is excited, the ionization energy is lower because the electron is already at a higher potential relative to the ground state. The answer to the student’s question is therefore (a) A little less than 13.6 eV.