Electron affinity??

Question

1) Why is group IIA very low in electron affinity?
2) Why is group VA very low in electron affinity?
3) Which has higher electron affinity?

A: Na or K
B: O or F
C: S or Cl
D: D or N
E: O or Se
F: Ca or Mg

Answer 1

Lancenigo di Villorba (TV), Italy

Electron Affinity interests the nature of the atomic orbitals available to Chemical Elements examined.
These orbitals may reserve two opposite possibilities, e.g. Electron-Gain or Electron-Losing.
Atoms showing residual void orbitals get favour to former possibility ; on the other hand, you have to consider the Orbital Energy-level or Ionization Energies for the outermost orbitals since you have to estimate the Losing possibility.
All these raisonings have to be executed on the basis of a Fundamental Energy Condition or Level, which is known as Fundamental Electronic Configuration of the Atom enquired.
Upon this basis, Pauling won Nobel's Prize introducing his Electronegativity's Number.


QUESTION 1)
Yes, it does.
Chemical Elements belonging to Group IIA (e.g. Beryllium, Magnesium, Calcium, Strontium, Barium and Radium) show atoms displacing two only electrons in its own outermost orbitals. These latters are defined as "s Orbitals" and it have the Low Ionization Energies ; moreover, there isn't another orbital and it cannot gain electrons.

QUESTION 2)
No, I would define medium level.
Chemical Elements belonging to Group VA (e.g. Nitrogen, Phosphorous, Arsenic, Antimony and Bismuth) show atoms displacing five electrons in its own outermost orbitals. These latters are distinguished as "s Orbitals" and "p Orbitals", where "p" reserve lower energies than "s" do.
Moreover, "p Orbitals" itself can fill its own void-status (e.g. these atoms show "p Orbitals" as HEMI-FULL ONEs) so it may gain electrons.

QUESTION 3)
Which has higher electron affinity?

A: Na or K I CHOOSEN Na
B: O or F I CHOOSEN F
C: S or Cl I CHOOSEN Cl
D: D or N I CHOOSEN N SINCE D EXISTS NOT
E: O or Se I CHOOSEN O
F: Ca or Mg I CHOOSEN Mg

How did I done? Simple : I choosen the chemical element showing the greatest ELECTRONEGATIVITY's Number as Pauling assigned them.

I hope this helps you..

Answer 2

1 and 2: think of filled and half filled shell stability. What orbital would an electron have to go into if you added it to Li? To Be? To B? To N? This should give you your answer.

3: Generally, as long as we are putting electrons into the same kind of orbital, electron affinity increases towards the top right-hand corner of the periodic table. In part D, do you mean "O or N"?