1. chlorine has a grater electron gain enthalpy than bromine
2. electron gain enthalpy of flourione is unexpectedly lower than that of chlorine.
3.  give reason why- ionic compound of the halogen contain singly charged X- ion and not doubly cahrged X-2 ions.
4. Li+ Be2+ B3+ which has  the smallest radius and why

5. O,N,P shows maximum covalency ?? why

6.

Dear patidarshm@gmail.com

In case of multiple questions within a query, please post each question individually and let us know where you are getting stuck so that we would be able to explain things better.

However, answer to your first query is,

Chlorine is smaller in size and has a smaller nuclear charge compared to bromine. Due to smaller size of chlorine, addition of electrons feel stronger attractions in chlorine. Hence, when an electron is added to the outermost shell of chlorine, less amount of energy is released. Consequently, chlorine has a higher electron gain enthalpy than bromine.

 

Regards

Topperlearning Team.