In the reaction `M+O_(2) to MO_(2)` (superoxide), the metal M is

Explanation

(i) Electronic configuration of `O_(2) = sigma1s^(2) sigma^(**)1s^(2) sigma2s^(2) sigma^(**)2s^(2) sigma2p_(z)^(2) pi2p_(x)^(2)= pi2p_(y)^(2), pi^(**)2p_(x)^(1)= pi^(**)2p_(y)^(1)`
Bond order `=(1)/(2) [10-6]=2`
It is paramagnetic in nature.
(ii) Electronic configuration of `O_(2)^(+)= sigma1s^(2) sigma^(**)1s^(2) sigma2s^(2) sigma^(**)2s^(2) sigma2p_(z)^(2) pi2p_(x)^(2)= pi2p_(y)^(2) pi^(**)2p_(x)^(1)= pi^(**) 2p_(y)^(0)`
Bond order `=(1)/(2)[10-5]=2.5`
It is paramagnetic in nature.
(iii) Electronic configuration of `O_(2)^(-) = sigma1s^(2) sigma^(**)1s^(2) sigma2s^(2) sigma^(**)2s^(2) sigma2p_(z)^(2) pi2p_(x)^(2)= pi2p_(y)^(2) pi^(**)2p_(x)^(2)= pi^(**)2p_(y)^(1)`
Bond order `=(1)/(2)[10-7]=1.5`
It is paramagnetic in nature.
(iv) (i) Electronic configuration of `O_(2)^(2-) = sigma1s^(2) sigma^(**)1s^(2) simga2s^(2) sigma^(**)2s^(2) sigmap_(z)^(2) pi2p_(x)^(2)= pi2p_(y)^(2) sigma^(**)2p_(x)^(2)= pi^(**)2p_(y)^(2)`
Bond order `=(1)/(2)[10-8]=1`
It is dimagnetic in nature.
Comparison of relative stability : Increasing order of relative stability of various species is as below:
`O_(2)^(2-) lt O_(2)^(-) lt O_(2) lt O_(2)^(+)`.