Question

Why does xenon form stable compounds with fluorine, whereas argon does not?

Short answer

Xenon forms stable compounds with fluorine due to its relatively larger atomic size and lower ionization energy, which allows it to form bonds with highly electronegative elements such as fluorine. In contrast, argon remains unreactive with fluorine because its smaller atomic size and higher ionization energy prevent it from forming stable bonds.

Step-by-step solution

Noble Gases: Electronic Configuration

Noble gases have complete electron shells, making them unreactive under normal conditions. This is because they have achieved a stable electron configuration, and their low reactivity is attributed to a high ionization energy required to remove an electron from their outermost shell. The full electronic configuration of xenon (Xe) is $$1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{10}4s^{2}4p^{6}4d^{10}5s^{2}5p^6$$. On the other hand, argon (Ar) has an electronic configuration of $$1s^{2}2s^{2}2p^{6}3s^{2}3p^6$$. Their full electron shells give them stability and make them unreactive under normal conditions.

Xenon: Reactivity with Fluorine

Xenon, being a heavier noble gas, has a larger atomic size and weaker hold on its valence electrons. This leads to a relatively lower ionization energy, making it somewhat easier to remove an electron from its outermost shell, compared to lighter noble gases. In the presence of highly electronegative elements, such as fluorine (F), xenon can form compounds like XeF2, XeF4, and XeF6. Fluorine, due to its high electronegativity, attracts the valence electrons from xenon, making it possible for xenon to form bonds and ultimately create stable compounds.

Argon: Non-Reactivity with Fluorine

Argon, being a lighter noble gas, has a smaller atomic size, and a stronger hold on its valence electrons. This results in a higher ionization energy, making it very difficult to remove an electron from its outermost shell. As a result, argon remains unreactive with electronegative elements like fluorine, as it cannot form stable bonds. In conclusion, xenon can form stable compounds with fluorine due to its relatively larger atomic size and lower ionization energy, allowing it to form bonds with highly electronegative elements. On the other hand, argon remains unreactive with fluorine as its smaller atomic size and higher ionization energy prevent it from forming stable bonds.