JEE Advanced · 2016 · 22 May 2016 · Paper 2 · Chemical Bonding and Molecular Structure

According to Molecular Orbital Theory,

Answer: (A), (C)

Solution

C_{2}^{2 -}

has 14 electrons with configuration

(σ_{1 s})^{2} (σ_{1 s}^{*})^{2} (σ_{2 s})^{2} (σ_{2 s}^{*})^{2} (π_{2 p})^{4} (σ_{2 p})^{2}

, all paired, hence diamagnetic.

N_{2}^{+}

(13 electrons, BO = 2.5) and

N_{2}^{-}

(15 electrons, BO = 2.5) have the same bond order.

O_{2}^{2 +}

has higher bond order than

O_{2}

, so shorter bond length.

He_{2}^{+}

has bond order 0.5, so it is stable and has lower energy than two isolated He atoms.

JEE Advanced · 2016 · 22 May 2016 · Paper 2 · One or more correct options