Why can't the ionisation enthalpy of two different elements be the same?
Dear Student,
Ionisation energy is a function of the electronic structure of the atom. The electronic structure of two elements cannot be same until they are isotopes. The first ionisation energy of isotopes will therefore be same as they have same number of protons and electrons and only differ in neutrons which donot affect the ionisation energy of an atom.
Now, no two different elements can have same number of protons and neutrons, therefore, ionisation energy of two different elements cannot be same.
Ionisation energy is a function of the electronic structure of the atom. The electronic structure of two elements cannot be same until they are isotopes. The first ionisation energy of isotopes will therefore be same as they have same number of protons and electrons and only differ in neutrons which donot affect the ionisation energy of an atom.
Now, no two different elements can have same number of protons and neutrons, therefore, ionisation energy of two different elements cannot be same.