question_answer 1)

    Explain why the electron gain enthalpy of fluorine is less negative than that of chlorine?

Answer:

  In fluorine, the electron is to be accommodated on second quantum energy shell. On account of small size, the electron density on this energy shell is very high. Thus, the electron to be accommodated experiences repulsion much more in comparison to chlorine atom in which the electron is accommodated on third quantum energy shell where space is more and electron density is comparatively less.