[uno]

Part I.
Consider the following neutral electron configurations in which n has a constant value. Which configuration would belong to the element with the most negative electron affinity,?

ns^2
ns^2np^2
ns^2np^5
ns^2np^6



Part II
Arrange the following elements from greatest to least tendency to accept an electron:

Be C Li O F

[Chemistry_Guru]

Part 1.

just remember that electron affinity of an atom or molecule is the amount of energy that would be required to detach an electron from a singly charged negative ion. so an equivalent defination is the energy released when an electron is attached to a neutral atom or molecule. So a positive electron affinity indicates that the energy is released on going from atom to anion.
electron affinity for nobel gases have not be conclusively measured. atoms whose anions are relatively more stable than neutral atoms have a greater electrons affinity and vice versa.
Generally nonmetals have more positive electron affinity than metals.

Part 2.
electron affinity generally increases across a period ( row) in teh periodic table, due to filling of the valence shells of the atom; a group 7A atom releases more energy than a group 1A atom on gaining an electron because it obtains a filled valence shell.
A trend of decreasing electron affinity going down the groups in the periodic table would be expected. the additional electron would be entering an orbital farther away from the nucleous, and thus would experience a lesser effective nuclear charge.

I hope that should help.


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