Choose the correct option regarding isoelectronic species.
1
Two or more species with same electronegativity but different ionization enthalpy
2
Two or more species with same number of atoms, same number of valence electrons and same structure, regardless of the nature of elements involved
3
Two or more species with same electron gain enthalpy but different electronegativity.
4
Two or more species with same ionization enthalpy but different electron gain enthalpy