Question

Among halogens, the correct order of amount of energy released in electron gain (electron gain enthalpy) is: (i) f > cl > br > i (ii) f < cl < br < i (iii) f < cl > br > i (iv) f < cl < br < i

Answer 1

Answer:

(iii)F <Cl>Br>I

Explanation:

We are given that F,Cl,Br and I

We have to arrange halogens in correct order of electron gain enthalpy.

Electron gain enthalpy: It is the amount of energy released when  an electron is added to isolated gaseous atom.

When we go from left to right in a period then electron gain enthalpy  due to increases addition of electron  in the same  shell and increase nuclear charge.

When we go down in a group then the electron gain enthalpy decreases due to addition of shell and increase in size.

Flourine is the smallest element of halogens family.The electron gain enthalpy of flourine is less than chlorine due to small size of flourine.

Therefore, the order of electron enthalpy of halogens is given by

Cl >F>Br >I

Asnwer:(iii)F <Cl>Br>I

Answer 2

Answer:

The electron gain enthalpy values of halogens become more negative in the order F>Cl>Br>I. ... However the electron gain enthalpy of F is less negative than of Cl because of its small size. The additional electron in case of F will be added to the 2p orbital while in case of Cl it will go in the 3p orbital.