Moving Charges And Magnetism

To determine the correct decreasing order of spin-only magnetic moment values for the ions , , , and , we need to analyze the electronic configuration of each ion and then apply the formula for the spin-only magnetic moment.

The formula for spin-only magnetic moment ( ) in Bohr Magnetons (BM) is given by:

where is the number of unpaired electrons.

1. For :
   • Electronic configuration of Cu: [Ar] .
   • Cu⁺ loses one electron: [Ar] .
   • Number of unpaired electrons ( ) = 0.
   • Magnetic moment = .
2. For :
   • Cu²⁺ loses two electrons: [Ar] .
   • Number of unpaired electrons ( ) = 1.
   • Magnetic moment = .
3. For :
   • Electronic configuration of Cr: [Ar] .
   • Cr²⁺ loses two electrons: [Ar] .
   • Number of unpaired electrons ( ) = 4.
   • Magnetic moment = .
4. For :
   • Cr³⁺ loses three electrons: [Ar] .
   • Number of unpaired electrons ( ) = 3.
   • Magnetic moment = .

Based on the calculations, the order of spin-only magnetic moment values is:

Thus, the correct answer is the option:

A species is paramagnetic if it has unpaired electrons:

• (paramagnetic) ✅
• (paramagnetic) ✅
• (paramagnetic) ✅
• (paramagnetic) ✅
• (paramagnetic) ✅
• (diamagnetic) ❌
• (diamagnetic) ❌
• (diamagnetic) ❌

Total paramagnetic species = 5.