Radon fluoride

Radon fluoride (RnF) is a compound of radon, an inert or noble gas. Inert gases are chemically unreactive because their outermost electron shells are completely filled with electrons. However, radon reacts readily with fluorine. The forces between radon's outermost electrons and the atomic nucleus are weakened by distance and the interference of other electrons, enough that the energy gained in creating a radon fluoride molecule is greater than the energy required for promotion of the reaction. The compound is chemically stable, although a powerful oxidizing agent. The usefulness of radon compounds is limited because the longest-lived isotope of radon has a half-life of only 3.82 days.