Question

Write the electron configuration for the first excited state for N₂; that is, the state with the highest-energy electron moved to the next available energy level. (a) Is the nitrogen in its first excited state diamagnetic or paramagnetic? (b) Is the N–N bond strength in the first excited state stronger or weaker compared to that in the ground state?

One electron is excited from the highest occupied MO (σ_2p) to the lowest unoccupied MO (π*_2p).

a) Excited state is paramagnetic since it has two unpaired electrons.

b) N–N bond of the first excited state is weaker compared to that in ground state, as electron moves from bonding to antibonding MO. The bond order drops from 3 to 2.