IIT JEE , AIEEE Forum - Chemistry , Inorganic Chemistry

amway

why is bond energy of F-F is less than Cl-Cl and Br-Br

sandeepramesh

F has smaller size, there is more interelectronic repulsion in

F-F than in Cl-Cl and Br-Br bcos they have large size

dream

hi
the bond energy of F-F is less than that of Cl-Cl and Br-Br because

bond energy not only depend upon electronegativity but also on other factors like EA

EA for Cl is max in gr 7 and hence this compensates for lesser EN of Cl than F

coming to Br, the other factors that affect bond strength is responsible here too, and the other factor again is its EA. additionally its dissociation energy also comes into picture here

hope that clears u

arpan1

can someone pls post the exact ans

sandeepramesh

excuse me dream but i fail to understand what reason you are implying! its clear that the reason is interelectronic repulsion

dream

sandeep according to ur explanation ,

F-F has lesser size so it is closer to nucleus and hence must have higher bond energy

but the case in here is contrary to what u r saying

sandeepramesh

@ arpan : Im pretty sure that the answer is small size of F and thereby the larger interelectronic repulsion between two F's ens therefore smaller bond disassociation energy

dream

well
yes interelectronic repulsion is also a part of explanation which i forgot to mention

but the effect of interelectonic repulsion is not the exact xplanation

the exact xplanation involves all the points that i have covered in my previous post

Ask & Discuss Questions with Community & Experts