Question

Which of the following diatomic molecular species has only $\pi$ bonds according to molecular orbital theory?

• A. $O_2$
• B. $N_2$
• C. $C_2$
• D. $B{e}_2$

Answer 1

The correct option is C $C_2$

The molecular orbital electronic configuration of $C_2$ is:
$\sigma$$1s^2$,${\sigma }^{\ast }$$1s^2$,$\sigma$$2s^2$,${\sigma }^{\ast }$$2s^2$,$\pi$$2p_x^2$ =$\pi$$2p_y^2$. Thus $C_2$ has only pi bonds according to molecular orbital theory.