Question

Rank the following diatomic species of oxygen in order of bond length and bond strength.

Options:
a) O2, O2-, O2
b) O2, O2, O2-
c) O2-, O2, O2
d) O2, O2-, O2-

Answer 1

The correct ranking in order of bond length starting with the longest and bond strength starting with the weakest is c) O2-, O2, O2+. This order is determined by the bond order of each species, with O2+ having the highest bond order and thus the strongest and shortest bond, O2 having a bond order of 2 and O2- having the lowest bond order.

Step-by-step explanation:

The question asks to rank the diatomic species of oxygen (O2, O2-, O2+) in order of bond length and bond strength. According to molecular orbital theory, as the bond order increases, the bond becomes stronger and the bond length becomes shorter. The oxygen molecule (O2) has a bond order of 2, superoxide ion (O2-) has a bond order of 1.5, and oxygen molecule cation (O2+) has a bond order of 2.5. Therefore, the strongest bond and shortest bond length is for O2+, followed by O2, and the weakest bond and longest bond length is for O2-. So, the correct ranking is c) O2-, O2, O2+.