Why does chlorine has more election gain enthalpy than fluorine

1.	Why does chlorine has more election gain enthalpy than fluorine
Answer» Though both fluorine and chlorine have same number of valence electrons, due to smaller valence orbital size of fluorine, the electron density in valence orbital is greater in fluorine than in chlorine. So, more effort would be required to insert a new electron in fluorine than in chlorine. So, chlorine has more negative electron gain enthalpy than in fluorine.

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