Paramagnetism

Definition

Paramagnetism is a form of magnetism that occurs due to the presence of unpaired electrons in an atom or molecule. These unpaired electrons align with external magnetic fields, causing a weak attraction.

5 Must Know Facts For Your Next Test

1. Paramagnetic substances have one or more unpaired electrons in their molecular orbitals.
2. In Molecular Orbital Theory, paramagnetism can be explained by the presence of unpaired electrons in degenerate orbitals.
3. A paramagnetic material will be attracted to an external magnetic field, but this effect is usually very weak compared to ferromagnetism.
4. The strength of paramagnetism is proportional to the number of unpaired electrons present in the substance.
5. Oxygen ($O_2$) is an example of a paramagnetic molecule due to its two unpaired electrons in antibonding molecular orbitals.

Review Questions

• What causes paramagnetism at the atomic level?
• How does Molecular Orbital Theory explain the paramagnetism of oxygen ($O_2$)?
• Why are substances with paired electrons not considered paramagnetic?

Related terms

Diamagnetism: A form of magnetism where materials are repelled by a magnetic field due to all their electrons being paired.

Ferromagnetism: A strong form of magnetism where materials can retain magnetic properties even after an external magnetic field is removed, due to aligned magnetic domains.

Molecular Orbital Theory: A theory that describes the electronic structure of molecules using quantum mechanics, where atomic orbitals combine to form molecular orbitals.