Which of the following electron distributions among the molecular orbitals best describes the NO molecule?
Σ_2s
Σ_2s^*
Π_2py=π_2px
Σ_2pz
Π_2py^*=π_2px^*
Σ_2pz^*

Question

Quizplus · Accepted Answer

The NO molecule has 10 electrons to distribute among the molecular orbitals. The molecular orbital diagram for NO is as follows:
Σ2s(2), Σ*2s(2)
Σ2p(2), Π2p(2), Σ*2p(2)
The electron configuration for NO is (σ2s)2(σ*2s)2(σ2p)2(π2p)2(σ*2p)2. This can be distributed among the molecular orbitals as follows: 
ΣS1U1B1: 2 electrons (from σ2s)
ΣS1U1B0: 2 electrons (from σ*2s)
ΣS1U1B1: 2 electrons (from σ2p)
ΠS1U1B1: 2 electrons (from π2p)
ΣS1U1B0: 1 electron (from σ*2p)
ΣP1U1B0: 1 electron (from σ*2p)
Therefore, the electron distribution among the molecular orbitals is: 2 2 4 2 1 0, which corresponds to choice C.

Which of the Following Electron Distributions Among the Molecular Orbitals