Bond order

Bond order of Ne₂

Bond order 0, diamagnetic. 20 electrons: Nb = 10, Na = 10.

Molecule or ion

Ne₂Neon (two atoms)

Bond order 0

20 electrons, all paired

i

Bond order zero: Ne2 does not exist.

20 electrons

0bond order
diamagnetic

(Nb − Na) / 2 = (10 − 10) / 2

σ1s² σ*1s² σ2s² σ*2s² σ2pz² (π2px² = π2py²) (π*2px² = π*2py²) σ*2pz²

Working

Bond order step by step

Ne₂ has 20 electrons: 10 from each Ne.
For O₂, F₂ and their ions, σ2pz lies below the π2p pair and fills first.
Configuration: σ1s² σ*1s² σ2s² σ*2s² σ2pz² (π2px² = π2py²) (π*2px² = π*2py²) σ*2pz²
Bonding electrons Nb = 10, antibonding electrons Na = 10.
Bond order = (Nb − Na) / 2 = (10 − 10) / 2 = 0.
Every electron is paired, so Ne₂ is diamagnetic.
A bond order of zero means there is no bond: Ne₂ is not a stable molecule.

Class 11, Chapter 4 Chemical Bonding and Molecular Structure.

Questions

What is the bond order of Ne2?

0. Bond order = (Nb − Na) / 2 = (10 − 10) / 2 = 0. Bonding electrons Nb = 10, antibonding electrons Na = 10.

Is Ne2 paramagnetic or diamagnetic?

Diamagnetic. Every electron is paired, so Ne₂ is diamagnetic.

What is the molecular orbital configuration of Ne2?

σ1s² σ*1s² σ2s² σ*2s² σ2pz² (π2px² = π2py²) (π*2px² = π*2py²) σ*2pz², with 20 electrons in all.