WHICH ARE THE ELEMENT OF LOWEST AND HIGHEST ELECTRON AFFINITY?

Asked by  | 25th Jun, 2008, 09:11: PM

Expert Answer:

The electron affinity is a measure of the energy change when an electron is added to a neutral atom to form a negative ion. For example, when a neutral chlorine atom in the gaseous form picks up an electron to form a Cl- ion, it releases an energy of 349 kJ/mol or 3.6 eV/atom. It is said to have an electron affinity of -349 kJ/mol and this large number indicates that it forms a stable negative ion. Small numbers indicate that a less stable negative ion is formed. Groups VIA and VIIA in the periodic table have the largest electron affinities.

* Alkali earth elements (Group IIA) and noble gases (Group VIIIA) do not form stable negative ions.

Period 2
Li
 
B
 
C
 
N
 
O
 
F
 
-0.62
 
-0.28
 
-1.27
 
0
 
-1.43
 
-3.41
Period 3
Na
 
Al
 
Si
 
P
 
S
 
Cl
 
-0.55
 
-0.46
 
-1.39
 
-0.75
 
-2.08
 
-3.62

Answered by  | 26th Jun, 2008, 12:13: PM

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