4. For the species O2, O2⁺ , and O2 ⁻ , use the molecular orbital model to give the electron configuration and the bond order for each. Which has the strongest bond?

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)