Find out the bond order in $He_2, He_2^{+}, O_2$ and $O_2^{+}$ respectively.

Which one of the following should be most stable?

Provide the electron configuration,magnetic property,bond order,and molecular orbital energy diagram for the fluorine $(F_2)$ molecule.

Given below are two statements:
Statement $I$: $A$ hypothetical diatomic molecule with bond order zero is quite stable.
Statement $II$: As bond order increases,the bond length increases.
In the light of the above statements,choose the most appropriate answer from the options given below.

The wave functions of $1s$-orbitals of two hydrogen atoms are $\psi_A$ and $\psi_B$. $\psi_A$ and $\psi_B$ are linearly combined to form two molecular orbitals ($\sigma$ and $\sigma^*$). Which of the following statements are correct?
$I$. $\sigma^*$ is equal to $(\psi_A - \psi_B)$.
$II$. In $\sigma$-orbital,one nodal plane is present in between two nuclei.
$III$. The energy of $\sigma$-orbital is lower than the energy of $\sigma^*$-orbital.

According to molecular orbital theory,antibonding molecular orbitals of $O_2$ contain