1. (5 points) Sulfur forms the hexafluoride, SF₆, which is completely unreactive toward water. In contrast, the selenium and tellurium analogs react with water (this reaction is called hydrolysis). Propose products for the reaction of SeF₆ with H₂O. Explain why the S and Se hexafluorides show such different reactivity toward water (hint: a thermodynamic argument won't work here; both compounds are thermodynamically unstable to hydrolysis.)

2. (5 points) Several interesting structures are shown in Figure 9.5, page 330 of Wulfsberg. Draw Lewis structures for S₂N₂ (d) and (NPF₂)₃ (e).

3. (5 points) On page 320 of Wulfsberg, under Group 14/4A, you will find the statement that "SnF₄ has a polymeric structure with bridging by half of the fluorine atoms." Propose a structure consistent with this statement.

4. (5 points) A chemist claims that he has synthesized a compound of formula NH₅. He suggests two possible structures for the compound. The first suggestion is that the compound consists of NH₅ molecules in which the stereochemistry at N is trigonal bipyramidal. The second suggestion is that the compound is ionic, with NH₄⁺ cations and H^- anions. Critique these two suggestions using as many structural principles as possible.