1. Electronic Configuration:

* An oxygen atom has 8 electrons, with the configuration 1s² 2s² 2p⁴.

* The 2p orbitals have two unpaired electrons, giving oxygen a paramagnetic character. This means it's attracted to external magnetic fields.

2. Molecular Orbital Structure:

* When two oxygen atoms combine to form a molecule (O₂), their atomic orbitals combine to form molecular orbitals.

* The molecular orbital diagram for O₂ shows that the 2p orbitals combine to form two degenerate π* antibonding orbitals, each with one unpaired electron.

3. Unpaired Electrons and Magnetism:

* These unpaired electrons in the π* antibonding orbitals are responsible for oxygen's paramagnetism. The unpaired electrons create a small magnetic dipole moment, which aligns with an external magnetic field.

4. Oxygen's Magnetic Behavior:

* Unlike diamagnetic materials, which are repelled by magnetic fields, oxygen is attracted to them due to its unpaired electrons.

* This paramagnetic behavior explains why liquid oxygen is attracted to magnets and why oxygen can be used in magnetic resonance imaging (MRI).

In summary, the molecular order structure of oxygen, with its unpaired electrons in the π* antibonding orbitals, explains its paramagnetic properties. This is a key factor in oxygen's role in various chemical and biological processes.