Question

How many of the following species are diamagnetic? $H{e}_2^{+},H_2,H_2^{+},H_2^{-},He$

• A. 1
• B. 2
• C. 3
• D. 0

Answer 1

Answer: (B)

According to molecular orbital theory, species with all paired electrons in their electronic configuration are diamagnetic in nature.

$H{e}_2^{+}\to$ Has total $3$ electrons, thus it contains one unpaired electron and is paramagnetic in nature.

$H_2\to$ Has total $2$ electrons, thus it contains all paired electrons and is diamagnetic in nature.

$H_2^{+}\to$ Has only $1$ electron, thus it is paramagnetic in nature.

$H_2^{-}\to$ Has total $3$ electrons, thus it contains one unpaired electron and is paramagnetic in nature.

$He\to$ Contains total two $(2)$ electrons and has no unpaired electron, thus is diamagnetic in nature. Hence, among the given species, we have only two of them which are diamagnetic and thus,