During change of O2 to O$$_2^{ - }$$ ion, the electron adds on which one of the following orbitals ?
C
$${\sigma ^ * }$$ orbital
Explanation
Electronic configuration of O2
$$\sigma 1{s^2}{\sigma ^*}1{s^2}\sigma 2{s^2}{\sigma ^*}2{s^2}\sigma 2p_z^2\pi 2p_y^2{\pi ^*}2p_x^1{\pi ^*}2p_y^1$$
Thus the incoming electron will enter in $$\pi ^*2p_x$$ to form $$O_2^+$$