Spin Quantum Number and Magnetism

Spin Quantum Number

• Allowed values: +1/2 (spin up) and -1/2 (spin down)
• Represents an electron's intrinsic angular momentum
• Electrons behave like tiny magnets due to their charge and spin

Paramagnetism vs. Diamagnetism

Paramagnetism

• Occurs when atoms or ions have unpaired electrons
• Unpaired electrons create a net magnetic field
• Attracted to external magnetic fields
• Can be determined using a special balance; the sample appears to gain weight when exposed to the field due to magnetic force

Diamagnetism

• Occurs when all electrons are paired
• No net magnetic field; fields cancel each other
• Weakly repelled by external magnetic fields
• Produces its own magnetic field in the opposite direction

Determining Magnetism: Electron Configurations

Helium

• Electron Configuration: 1s²
• All electrons paired: Diamagnetic

Carbon

• Electron Configuration: 1s² 2s² 2p²
• Unpaired electrons in 2p orbital: Paramagnetic

Sodium

• Electron Configuration: 1s² 2s² 2p⁶ 3s¹
• One unpaired electron in 3s orbital: Paramagnetic

Sodium Ion (Na⁺)

• Electron Configuration: 1s² 2s² 2p⁶
• All electrons paired after losing one electron: Diamagnetic

Key Concepts

• Paramagnetic: Unpaired electrons, attracted to magnetic fields
• Diamagnetic: Paired electrons, not attracted (repelled) by magnetic fields
• Use electron configurations to determine the magnetic properties of atoms and ions.