What is the number of electrons present in antibonding orbitals of $N_2$ molecule according to molecular orbital theory?

Select the correct order $-$

If $x-axis$ is the molecular axis and $p_z$ orbitals participate in bonding,then which one of the following will be the nodal plane present within the $\pi-$ bond of the $O_2$ molecule?

What is meant by the term bond order? Explain.

Which of the following species is paramagnetic?

What is the correct sequence of bond order for the given species?