Which of the following molecules does not exist on the basis of Molecular Orbital Theory?

What is meant by the term bond order? Calculate the bond order of: $N_{2}, O_{2}, O_{2}^{+}$ and $O_{2}^{-}$

Which of the following molecular orbitals has the maximum number of nodal planes?

Given below are two statements:
Statement $I$: $A$ $\pi$ bonding $MO$ has lower electron density above and below the inter-nuclear axis.
Statement $II$: The $\pi^*$ antibonding $MO$ has a node between the nuclei.
In the light of the above statements,choose the most appropriate answer from the options given below:

During the change of $O_2$ to $O_2^-$ ion,the electron adds to which one of the following orbitals?

Which of the following is paramagnetic?