Home › MCQs › JEE MAIN Chemistry › Question #5545
Back to Questions
JEE MAIN Chemistry QUESTION #5545
Question 1
In which of the following pairs of molecules/ions are BOTH species unlikely to exist?
  • $H_2^+,\ He_2^{2-}$
  • $H_2^-,\ He_2^{2-}$
  • $H_2^{2+},\ He_2$✔️
  • $H_2^-,\ He_2^{2+}$
Correct Answer Explanation
Bond order = $\frac{1}{2}(\text{bonding} - \text{antibonding electrons})$. $H_2^{2+}$: 0 electrons, BO = 0 → does not exist. $He_2$: 2 bonding + 2 antibonding, BO = 0 → does not exist. Therefore both $H_2^{2+}$ and $He_2$ cannot exist, making option C correct.