10. Why does sulfur form catenated polysulfides of formula [SSS]2 and [SSSSS]2 Whereas polyoxygen anions beyond O3are unknown? Explain. 11. Xenon is very unreactive but forms a few compounds with oxygen and fluorine such as XeO4. Predict and draw the shape of XeO4 and identify the Z+22 compound with the same structure. Show your work. 12. Give the expected maximum stable oxidation state for (a) Ba, (b) As, (c) P, (d) Cl. Give examples. 13. The elements vary from metals through metalloids to nonmetals. They form halides in oxidation states +5 and +3 and the hydrides are all toxic gases. Identify this group of elements. Give details. 14. Identify the Z+8 element for S. Briefly summarize any similarities between the elements. 15. Describe the general trend in atomic and ionic radii in the periodic table? Does it affect the chemistry of the element? 16. Explain the general trend in first ionization enthalpies and explain with example the anomalies in the trend. 17. State to which period, group, and block of the periodic table the element with the electron configuration 1s22s22p63s23p64s1 and [Ar]4s23d104p4; belongs. Identify the element. Explain how did you get your answer. 18. Describe with examples the diagonal relationship between Li and Mg