[BriaM]

Someone please help me! 

Given the following data, estimate the energy released when gaseous K and I atoms form gaseous [K+I-]. neglect anything about lattice information

Element EA (kJ/mol)      IE1 (kJ/mol)        IE2 (kJ/mol)         Ion Radius( pm)
K                -48.4            418.8             3051       133(cation)
I                 -295.3           1008.4           1845.9      220 (anion)

The answer is -270kj/mol
please anyone help me on how to get this question because am stuck.. also frustrated..ugg! ;( I'm not even sure of how to approach it.

[fledarmus]

In your own words, what information are you given in the table you posted?

[BriaM]

I am given the electron affinities for potassium and iodine which are -48.4 and -295.3. Then I have the first and second ionization energies for both elements. Potassium at 418.8 and 3051 respectively and iodine with 1008.4 and 1845.9. The electron affinity and ie have units of kj/mol. Finally we are given the ion radius with potassium at 133 pm and iodine at 220 pm. We have to neglect lattice formation. I tried incorporating Coloumbs law but we aren't allowed to use it...

[fledarmus]

What reaction does the energy of ionization represent?

[BriaM]

The minimum energy need to remove the highest energy electron from the neutral ago
   In the gaseous state

[BriaM]

Anyone?

[fledarmus]

Okay, so how would you write that reaction?

And likewise, what reaction does the electron affinity represent? And how would you write that reaction?

[BriaM]

Yeah, nevermind. I used the equation E = kQ1Q2/r. plugged in values and got -270.