13. For many years after they were discovered, it was believed that the noble gases could not form compounds. Now we know that belief to be incorrect. A mixture of xenon and fluorine gases, confined in a quartz bulb and placed on a windowsill, is found to slowly produce a white solid. Analysis of the compound indicates that it contains 77.55% Xe and 22.45% F by mass. What is the formula of the compound? Write a Lewis structure for the compound. Predict the shape of the molecules of the compound. What hybridization is consistent with the shape you predicted?

The elements in which the extra electron tends to enter the 5f-orbitals of (n–2)th main shell are considered 5f-block elements. They are also named actinides. Actinides include 15 elements, from atomic number 89 to 103.