Energy of an electron in the ground state of the hydrogen atom is –2.18×10–18J. Calculate the ionization enthalpy of atomic hydrogen in terms of J mol–1.

Hint: Apply the idea of mole concept to derive the answer.

Ionization enthalpy is the minimal quantity of energy which is demanded to get rid of the most loosely bound electron from a neutral isolated gaseous atom to form a cation.

It is given that the energy of an electron in the ground state of the hydrogen atom is -2.18 × 10-18J.


So, Ionization enthalpy of atomic hydrogen = 2.18 × 10-18 J.


So, converting the ionization enthalpy from Joules to J/mole


= 2.18 × 10-18 × 6.02 × 1023 J mol-1


= 1.31 × 106 J mol-1


Therefore, the ionization enthalpy of hydrogen atom is 1.31 × 106 J mol-1.


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