Factors affecting electron affinity & important questions answer

Factors affecting electron affinity: 

1.Effective nuclear charge :
more is the nuclear charge, more is the attraction for extra electron, more is the amount of energy   released and hence more will be the electron affinity.

2.Atomic size:
small is the size of atom, more is the attraction forextra electron and hence more will be electron affinity.


3.Electronic configuration: 
elements having half filled and fully filled configuration are very stable so that have little tendency to except electron or no tendency to except extra electron. so they have very low value of electron affinity or zero electron affinity.

Question /Answer

1.Electron affinity of noble gases is zero?
ans
because of more stability of completely filled valence shell they have no tendency to gain electron  hence electron affinity of noble gases are zero.

2.Nitrogen and phosphorus have low value of electron affinity?
ans
N
(7)  1s^2 2s^2 2p^3

P
(15)  1s^2 2s^2 2p^6 3s^2  3p^3

the electronic configuration of nitrogen and phosphorus is quite stable because they have exactly half filled p sub shell. so they have little tendency to except extra electron  hence nitrogen and phosphorus have low value of electron affinity.

3.While Electron affinity of fluorine is less than chlorine?
ans

Due to small size of fluorine .intermolecular electron replusion are more so addition of extra electron is some what difficult so electron affinity of fluorine is less than chlorine.


similar question

4.While Electron affinity of oxygenis less than sulphur?

Question 5.
Electron affinity of halogen are very high.
ans
halogen have 7 electron in their valence shell (ns^2np^5)  they have string tendency to accept additional electron so has to change into ion having noble gas configuration of noble gas hence electron affinity of halogenare very high.

Question 6
fluorine is better oxidesing agent than chlorine?
ans
Oxidesing agent: ( non metal)  those substance which can gain electron .
Reducing agent: (metal)  those substance which can lose electron.
fluorine is better oxidesing agent because fluorine has lower dissociation energy than dissociation energy of chlorine.

Be, Mg have electron affinity is zero due to half filled and completely filled electronic configuration in subshell.

Question 7
Difference between electron affinity and electronegativity?
ans
Electron affinity :
1.the amount of energy released when extra electron adding the neutral atom and formed gaseous atom anion.
2.it is the property if isolated atom.
Electronegativity:
1.the tendency to attract shared pair of electron towards inside is called electron negativity.