Question

According to molecular orbital theory, which of the following will not exist?

• A. $H_{2}^{+}$
• B. $Be_{2}$
• C. $B_{2}$
• D. $C_{2}$

Answer 1

Answer: (B)

$Be_{2}$

Answer 2

: $Be_{2}(\sigma 1s^{2})(\sigma*1s^{2})(\sigma 2s^{2})(\sigma*2s^{2})$

B.O. $= \frac{1}{2}(N_{b} - N_{a}) = \frac{1}{2} \times (4 - 4) = 0$

Since B.O. is zero the molecule does not exist.