3. Write Lewis structures and predict the molecular structures of XeF4, SO3, BrF3, and IF5. Which of these compounds are polar? (15%) －

2. The reaction of ethane gas (C2H6) with chlorine gas produces C2H5Cl as its main product (along with HCl) and a variety of other minor products. Calculate the percent yield of C2H5Cl if the reaction of 300. g of ethane with 650. g of chlorine produced 490. g of C2H5Cl. (atomic mass: C, 12.01； Cl, 35.45； H, 1.008) (8%)