Introduction to d-Block and f-Block Elements

• Elements are classified based on the block of the periodic table they occupy, determined by the type of atomic orbital being filled.

• d-Block Elements: Groups 3–12, transition metals, outermost electrons in d-orbital.

• f-Block Elements: Lanthanides and Actinides, electrons fill f-orbitals.

• NEET emphasizes conceptual understanding of properties, trends, and reactivity, rather than rote memorization.

Key Concept: The partially filled d- or f-orbitals govern metallic character, variable oxidation states, and catalytic behavior.

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d-Block Elements (Transition Metals)

General Properties

• High melting and boiling points

• Good conductors of heat and electricity

• Malleable and ductile

• Form colored compounds (due to d-d transitions)

• Exhibit variable oxidation states (common NEET focus)

• Form complex ions with ligands

• Catalytic properties (Fe in Haber process, V₂O₅ in Contact process)

Conceptual Focus: Link partially filled d-orbitals → colored compounds → catalytic behavior → variable oxidation states.

Trends in d-Block Elements

1. Atomic and Ionic Size: Slight decrease across the period due to increasing nuclear charge

2. Ionization Energy: High, but less variation due to inner d-electrons

3. Oxidation States:

   • Early transition metals: lower oxidation states stable (e.g., Ti²⁺, V³⁺)

   • Middle metals: multiple oxidation states (Fe²⁺, Fe³⁺)

   • Later metals: higher oxidation states less stable

4. Electronegativity and Reactivity: Moderate; reactivity generally lower than s-block metals

NEET Tip: Focus on why variable oxidation states occur — due to small energy difference between ns and (n-1)d electrons.

Important Reactions and Applications

• Formation of Complexes: [Fe(CN)₆]³⁻, [Cu(NH₃)₄]²⁺

• Catalysis:

  • Fe → Haber process

  • V₂O₅ → Contact process

• Alloys: Stainless steel (Fe + Cr + Ni)

Conceptual Link: Partially filled d-orbitals allow bonding flexibility and catalytic activity.

f-Block Elements (Lanthanides and Actinides)

Lanthanides (Ce-Lu)

Properties:

• Also called rare earth elements

• Similar chemical properties (hard to separate)

• Exhibit +3 oxidation state predominantly

• Form oxides and halides

• Paramagnetic due to unpaired f-electrons

Trends:

• Lanthanide contraction: gradual decrease in atomic and ionic size across the series

• Increasing density and hardness

• High melting and boiling points

NEET Tip: Focus conceptually on lanthanide contraction → effect on subsequent elements’ chemistry.

Actinides (Th-Lr)

Properties:

• All are radioactive

• Show multiple oxidation states (mainly +3, +4)

• Form complex ions and oxides

• Mostly metallic with high density and melting points

Trends:

• Actinide contraction: similar to lanthanide contraction, less pronounced

• Reactivity decreases slightly down the series

• Many are synthetic elements with short half-lives

Conceptual Focus: NEET usually asks about radioactivity, oxidation states, and actinide-lanthanide comparison.

Comparative Features of d-Block and f-Block Elements

Applications

d-Block Elements:

• Catalysts: Fe, Ni, V₂O₅

• Alloys: Stainless steel, brass, bronze

• Electronics: Cu wires, Ag plating

f-Block Elements:

• Lanthanides: Phosphors in TVs and LEDs, strong magnets (NdFeB)

• Actinides: Nuclear fuel (U, Pu), radioactive tracers

NEET Tip: Conceptually connect structure → properties → applications.

Quick Concept Summary Table

Conclusion

The d-Block and f-Block Elements chapter is essential for NEET Chemistry. Conceptual understanding focuses on:

• Transition metals: partially filled d-orbitals → variable oxidation states, catalytic properties, colored compounds

• Lanthanides: +3 oxidation state, lanthanide contraction, paramagnetism

• Actinides: radioactivity, multiple oxidation states, nuclear applications

By understanding structure → properties → trends → applications, NEET aspirants can confidently tackle reasoning-based and conceptual questions.

StudentBro.in provides structured, fully conceptual notes to help NEET aspirants master d- and f-block elements efficiently, with H4 bold headings for readability and SEO optimization.