The number of unpaired electrons in $O_2$ molecule is

Which of the following pairs have identical values of bond order?

In which of the following processes does the value of bond order and magnetic nature not change?

Which of the following statements is correct regarding the formation of dioxygen $(O_2)$ from oxygen atoms?

Which of the following linear combinations of atomic orbitals will lead to the formation of molecular orbitals in homonuclear diatomic molecules [internuclear axis in $z$-direction]?

What is $LCAO$? Explain.