Magnetic Properties of d and f Block Elements - NEET Notes, Formula & Common Mistakes
Magnetic propertiesd and f Block ElementsNEET ChemistryNEET 2025ParamagnetismDiamagnetismMagnetic Moment
Magnetic Properties of d and f Block Elements - NEET Notes, Formula & Common Mistakes
d and f Block Elements·2 min read·NEET 2026
What NEET Asks
Identification: Questions on identifying paramagnetic or diamagnetic species based on electron configuration.
Calculation: Direct application of the spin-only formula to calculate magnetic moment.
Comparison: Comparing magnetic moments of different ions or correlating magnetic moment with the number of unpaired electrons.
Key Points
Paramagnetism: Substances weakly attracted by magnetic fields, possessing one or more unpaired electrons. The more unpaired electrons, the stronger the paramagnetism.
Diamagnetism: Substances weakly repelled by magnetic fields, having all electrons paired. They have zero magnetic moment.
Origin: Magnetic properties primarily arise from the spin motion of electrons. Orbital motion is generally neglected for first-row transition metals in NEET calculations.
Spin-Only Formula: Magnetic moment (μ) is calculated using μ = √n(n+2) BM, where 'n' is the number of unpaired electrons.
d-Block Trends: Magnetic moment typically increases with 'n' up to d⁵ configuration, then decreases as electrons start pairing up.
Lanthanoids: Exhibit strong paramagnetism due to well-shielded 4f electrons, and orbital contribution is significant.
Must-Know Formula / Reaction
Spin-only Magnetic Moment:
μ = √n(n+2) BM
μ: Magnetic moment in Bohr Magnetons (BM)
n: Number of unpaired electrons
Common Mistakes
Students often miscalculate the number of unpaired electrons for transition metal ions, especially when dealing with anomalous configurations or higher oxidation states.
Students often forget to remove electrons from the outermost s-orbital first, before the d-orbital, when forming transition metal cations.
Rapid Revision
Paramagnetic species have unpaired electrons (n>0) and a non-zero magnetic moment (μ = √n(n+2) BM). Diamagnetic species have all paired electrons (n=0) and μ = 0 BM. Accurately determining 'n' from the ion's electronic configuration is key.
Frequently Asked Questions
What causes magnetic properties in d and f block elements?▾
Magnetic properties in d and f block elements primarily arise from the presence of unpaired electrons. These electrons have both spin and orbital angular momentum, creating tiny magnetic dipoles that interact with an external magnetic field.
How do I determine if a transition metal ion is paramagnetic or diamagnetic?▾
To determine this, first write the electronic configuration of the metal ion. If there are any unpaired electrons in the d or f orbitals, the ion is paramagnetic. If all electrons are paired, the ion is diamagnetic.
Is the spin-only formula accurate for all transition metal complexes?▾
The spin-only formula (μ = √n(n+2) BM) is generally a good approximation for first-row transition metal ions where the orbital angular momentum contribution is often quenched. However, for heavier transition metals and lanthanoids, the orbital contribution to the magnetic moment can be significant and should ideally be considered for more accurate values.
Practice MCQs on this topic
Interactive questions with instant AI explanations