Expert: Sherman D. - 12/14/2004

Question
Which group 18 element is most likely to form a compound with the element flourine?
1. He
2. Ne
3. Ar
4. Kr
The answer is Kr, but I don't get why.Please explain. My teacher told us the answer, but didn't explain it well and there is a test tomorrow.Please help.


Answer
Flourine = 1 electron left
Helium = 2 electrons left
Neon = 2 electrons left
Argon = 2 electrons left
Krypton = 4 electrons left

Krypton difluoride, KrF(little 2), has been prepared in gram quantities and can be made by several methods.
Found at www.webelements.com/webelements/elements/text/Kr/key.html

But my main guess would be because Fluorine combined with Krypton is closer to filling up its outermost shell than if Fluorine were to combine with the other elements.

It would take more flourine to help the other elements to fill up their outermost shell.

I don't know for sure if shell is the term for the outermost area of the atom.