Question

Assertion $He_2$ does not exist.
Reason Bond order of $He_2$ is zero.

• A. Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
• B. Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
• C. Assertion is true but Reason is false.
• D. Both Assertion and Reasonlare false.

Answer 1

Answer: (A)

$He_2$ does not exist because bond order of $He_2^+$ is zero.Molecular orbital configuration of $ He_2=\sigma 1s^2, \sigma^* 1s^2$
$\, \, \, \, \, \, \, \, \, \, \, \, \, =\frac{N_b-N_a}{2}$
$\, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, =\frac{2-2}{2}=0$