Research On Electron Affinity

 The amount of energy released when an electron is added to valence shell of a neutral isolated gaseous atom of an element is called Electron Affinity

Electron Affinity (EA)  is measured in ev/atom, Kcal/mol, KJ/mol. EA can be calculated indirectly from Born Haber Cycle. 

Noble gases have most stable electronic configuration. Hence their EA values are practically zero. 

First EA(Electron Affinity)

 EA1 is negative for all elements except Be,  Mg,  N atoms. 

Be(+66KJ/mol)

Mg(+67KJ/mol)

N (+31 K/mol)

In groups EA(Electron Affinity) decreases from top to bottom as the atomic size increases

EA ( Electron Affinity)  of third period element is greater than second period element of each group 

In 

VII A group- EA( Electron Affinity)  of Chlorine(Cl) > EA( Electron Affinity) of Fluorine (F) 

VI A group EA of Sulphur (S) > EA of oxygen (O) 

V A group EA of phosphorus (P)  > EA of Nitrogen (N) 

IV A group EA of silicon (Si) > EA of Carbon (C) 

EA of F - (-333 KJ/mol)

EA of Cl- (-348 KJ/mol)

A more points will be added stay tuned