In which of the following pairs of molecules/ions both the s... | Chemistry | SolveeIt

Question

In which of the following pairs of molecules/ions both the species are not likely to exist?

$H_2^+ , He_2^{2-}$

$H_2^- , He_2^{2-}$

$H_2^{2+} , He_2$

$H_2^- , He_2^{2+}$

Answer

$H_2^{2+} , He_2$

Explanation

Solution

Species having zero or negative bond order do not exist
$H_2^{2+} (1 + 1 - 2 = 0) = \sigma ls^0$
Bond order = 0
$He_2 (2 + 2 = 4 ) = \sigma ls^2 , _{\sigma}^{*} ls^2$
Bond order $= \frac{N_b - N_a}{2} = \frac{2 - 2}{2} = 0$
So, both $H_2^{2+}$ and $He_2$ do not exist.

Chemistry Question on Chemical bonding and molecular structure

Solution