The correct order of energies of molecular orbitals of N$$_2$$ molecule is:

Question

Accepted Answer

1. **General Rule:** For homonuclear diatomic molecules of the second period, the order of molecular orbital energies depends on the number of electrons.
2. **Molecules with Z > 7 (O$${_2}$$, F$${_2}$$, Ne$${_2}$$):** The energy of the $$\sigma 2p_z$$ orbital is lower than that of the $$\pi 2p_x$$ and $$\pi 2p_y$$ orbitals .
3. **Molecules with Z $$\le$$ 7 (Li$${_2}$$, Be$${_2}$$, B$${_2}$$, C$${_2}$$, N$${_2}$$):** Experimental observations show a different order due to the mixing of 2s and 2p orbitals (s-p mixing). In these cases, the energy of the $$\sigma 2p_z$$ orbital is **higher** than that of the $$\pi 2p_x$$ and $$\pi 2p_y$$ orbitals .
4. **Specific Order for N$${_2}$$:** The increasing order of energies is:
   $$ \sigma 1s < \sigma^* 1s < \sigma 2s < \sigma^* 2s < (\pi 2p_x = \pi 2p_y) < \sigma 2p_z < (\pi^* 2p_x = \pi^* 2p_y) < \sigma^* 2p_z $$
   This corresponds to Option A.

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