Question

Using molecular orbital theory predict the correct decreasing bond order of the following species

$1.O_{2}^{+}$ $2.O_{2}^{-}$ $3.O_{2}^{2 -}$ $4.O_{2}^{2 +}$

• A. 1 > 2 > 3 > 4
• B. 4 > 1 > 2 > 3
• C. 4 > 1 > 3 > 2
• D. 1 > 4 > 2 > 3

Answer 1

Answer: (B)

Bond order $=\frac{\text{no.of bonding } \bar{e} - \text{no. of anti bonding } \bar{\text{e}}}{2}$

Bond orders of $O_{2}^{+}\text{,}O_{2}^{-}\text{,}O_{2}^{2 -}\text{and}O_{2}^{2 +}$ are respectively 2.5, 1.5, 1 and 3

Hence $O_{2}^{2 +}$ has max bond order is

$O_{2}^{2 +} > O_{2}^{+} > O_{2}^{-} > O_{2}^{2 -}$