Question

The correct statement with regard to $H_2^{+}$ and $H_2^{-}$ is:

• A. both $H_2^{+}$ and $H_2^{-}$ are equally stable
• B. both $H_2^{+}$ and $H_2^{-}$ do not exist
• C. $H_2^{-}$ is more stable than $H_2^{+}$
• D. $H_2^{+}$ is more stable than $H_2^{-}$

Answer 1

Answer: (D)

$H_2^{+}$ is more stable than $H_2^{-}$

Electronic configuration of $H_2^{+}$ is $\sigma 1s^1{\sigma }^{\ast }1s^0$

Bond order will be $1-0/2=1/2$

Electronic configuration of $H_2^{-}$ is $\sigma 1s^2{\sigma }^{\ast }1s^1$

Bond order will be $2-1/2=1/2$.

Bond order for both $H_2^{+}$ and $H_2^{-}$ is same but $H_2^{+}$ is more stable than $H_2^{-}$ due to absence of electrons in anti-bonding orbital.