Write the MO electron distribution of O₂.Specify its bond order and magnetic property.

To determine the molecular orbital (MO) electron distribution of O₂, we first need to understand how the molecular orbitals are filled based on the energy levels of the atomic orbitals from the oxygen atoms. Oxygen has an atomic number of 8, which means each oxygen atom contributes 8 electrons, leading to a total of 16 electrons for the O₂ molecule.

Filling the Molecular Orbitals

The molecular orbitals for O₂ are filled according to the Aufbau principle, Hund's rule, and the Pauli exclusion principle. The order of energy levels for the molecular orbitals in O₂ is as follows:

• σ_1s
• σ_1s*
• σ_2s
• σ_2s*
• σ_2pz
• π_2px
• π_2py
• π_2px*
• π_2py*

Now, let's fill these orbitals with the 16 electrons:

• σ_1s: 2 electrons
• σ_1s*: 2 electrons
• σ_2s: 2 electrons
• σ_2s*: 2 electrons
• σ_{2pz: 2 electrons}
• π_{2px: 2 electrons}
• π_{2py: 2 electrons}
• π_{2px*: 1 electron}
• π_{2py*: 1 electron}

After filling the orbitals, the electron configuration of O₂ can be summarized as:

σ_1s² σ_1s*² σ_2s² σ_2s*² σ_{2pz² π2px² π2py² π2px*¹ π2py*¹}

Calculating Bond Order

The bond order can be calculated using the formula:

Bond Order = (Number of bonding electrons - Number of antibonding electrons) / 2

In O₂, we have:

• Bonding electrons: 10 (σ_1s², σ_2s², σ_{2pz², π2px², π2py²)}
• Antibonding electrons: 6 (σ_1s*², σ_2s*², π_{2px*¹, π2py*¹)}

Plugging these values into the bond order formula gives:

Bond Order = (10 - 6) / 2 = 2

Magnetic Properties

O₂ is known to be paramagnetic due to the presence of two unpaired electrons in the π_{2px* and π2py* orbitals. Paramagnetic substances are attracted to magnetic fields because of these unpaired electrons, which can align with the magnetic field. This is a distinctive property of O2, making it different from many other diatomic molecules that are diamagnetic (having all paired electrons).}

In summary, the molecular orbital electron distribution of O₂ reveals a bond order of 2 and exhibits paramagnetic behavior due to the presence of unpaired electrons. This understanding of molecular orbitals not only helps in predicting the properties of O₂ but also provides insights into its reactivity and interactions with other molecules.