A simple question.

[KingNothing]

Why in the world does Xe react with O_2PtF_6 to form XePtF_6?

[so-crates]

This is one of those cases where a simplistic view of the atom and and the octet rule are insufficient to describe what is going on.

However, keep in mind that flourine, being the most electronegative element, is going to be the best canidate to draw electrons away from anything. And Xeon, being the largest (stable) noble gas, is going to be the most likely of the noble gases, if any, to share its electrons since there are furthest away from the nucleus.

I realize I didn't really answer your question but gave only plausible explanations for why it might occur. Actually, I'm not sure if anyone really understands why its stable. Theoretically, you could calculate the wave function of every single electron in the bond, but I'm not sure if anyone has done that. What level chemistry are you taking again?

[KingNothing]

The first level. But its really easy so I'm trying to ask harder questions of the subject.

[chem_tr]

KingNothing, I am not sure if you correctly wrote the hexafluoroplatinate; I suppose some other positively charged element like potassium, sodium, etc., to be instead of O2???

So-crates is right about its reactivity, the outmost shell is more prone to electronic modifications than any lower homologues. Radone is too reactive (radioactive) to be so stable, so this is usually not considered as a "stable" noble gas.

Remember again, that the compound formed (including xenon as a cation) is stable only in low temperatures, disturbing it with some heat will cause elemental xenon to be formed. I think in this case, xenon difluoride, elemental xenon, and tetrafluoroplatinate species might occur.

[KingNothing]

What are homologues? Other elements? Lower energy levels? Why is Radon radioactive? Also, what is a Cation? Also, how low are the temperatures?

[Astronuc]

See the following on Webelements:

XeF2 (http://www.webelements.com/webelements/compounds/text/Xe/F2Xe1-13709369.html)
XeF4 (http://www.webelements.com/webelements/compounds/text/Xe/F4Xe1-13709610.html)
XeF6 (http://www.webelements.com/webelements/compounds/text/Xe/F6Xe1-13693099.html)

Apparently XeF6 is so reactive (more so than lower order fluorides), it cannot be contained in dry quartz.

Radon is radioactive because it has a sufficient excess of neutrons. Rn has Z=86. Lighter radioactive neighbors include Polonium (Z=84) and Astatine (Z=85). Bismuth is the heaviest element with a stable isotope (Bi-209).

Cation is a positive ion.