Answer to Question #338343 in Inorganic Chemistry for jhnhjbjb

Question

The bond energy of F₂ is unusually low, in comparison with the other halogens, due to the small size of the fluorine atom. Which of the following periodic properties is also unusually low in the case of fluorine?

Answer 1

(i) I2​<F2​<Br2​<Cl2​ The electron affinity of Chlorine is maximum in the periodic table and so the bond dissociation enthalpy. Flourine has lower  bond dissociation enthalpy than Br2​ and Cl2​. Due to small size electronic repulsion is very high. I2​ has lowest bond dissociation enthalpy due to quite larger size it is easiest to break the bond.
(ii) HF<HCl<HBr<HI⇒Acidic strength of Halogen acids increases down the group.
(iii) BiH3​<SbH3​<AsH3​<PH3​<NH3​⇒ Basic strength decreases down the group because as we go down the group the size of the atom and thus the electron density decreases. These compounds are lewis base having 1 lone pair on the central atoms. As the electron density decrease the tendency to donate electron pair decreases.