Classification Of Elements And Periodicity In Properties Ques 63
Question: Which one of the following arrangements represents the correct order of electron gain enthalpy (with negative sign) of the given atomic species [CBSE PMT 2005]
Options:
A) $ Cl<F<S<O $
B) $ O<S<F<Cl $
C) $ S<O<Cl<F $
D) $ F<Cl<O<S $
Show Answer
Answer:
Correct Answer: B
Solution:
Halogens have very high electron affinities. It may be noted that the electron affinity of fluorine is unexpectedly low $ (<Cl) $ . This may perhaps be due to the small size of the F atom. The values of electron gain enthalpies for Cl,F, S and O are respectively 349, 333, 200 and 142 kJ/mole hence correct order is Cl>F>S>O.
