Question

Identify a molecule which does not exist

• A. $B{e}_2$
• B. $N_2$
• C. $B_2$
• D. $C_2$

Answer 1

The correct option is A $B{e}_2$

$B{e}_2\left(8e^{-}\right):\sigma 1s^2{\sigma }^{\ast }1s^2\sigma 2s^2{\sigma }^{\ast }2s^2$
$BO=\frac{1}{2}(N_b-N_a)=\frac{1}{2}(4-4)=0$
$\Rightarrow$ Bond order of $B{e}_2=0$
$\therefore B{e}_2$ doesn’t exist.