Question

The paramagnetic character in the 3d-transition series elements increases up to Mn and then decreases.

Explain the following:

The paramagnetic character in 3d-transition series elements increases upto Mn and then decreases.

Answer 1

1. Paramagnetism arises from unpaired (n − 1)d electrons.
2. Across the 3d series, the number of unpaired electrons increases to five at Mn (3d⁵), so paramagnetism rises.
3. After Mn, additional electrons pair up in d‑orbitals, decreasing the number of unpaired electrons and thus paramagnetism.
4. Magnetic moment μ ≈ `sqrt[n(n+2)]` BM, which peaks when n = 5 (Mn).