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Periodic Table & p-Block Elements
Trends, s-block, p-block and d-block element properties
Key Concepts
- Atomic radius decreases across a period; increases down a group
- Ionisation energy (IE₁) increases across period; decreases down group
- Electronegativity: F is the highest; increases across period, decreases down group
- Electron affinity: generally increases across period; Cl > F due to small size of F
- Diagonal relationship: elements diagonally adjacent have similar properties (Li–Mg, Be–Al)
Important Formulae
| Slater's shielding constant (σ) | Z_eff = Z − σ (effective nuclear charge) |
Quick Tips
- IE₁ of N > O because N has a stable half-filled p subshell (3 unpaired electrons).
- Transition metals show variable oxidation states due to involvement of d electrons.
- Lanthanide contraction: f electrons shield poorly → similar radii for lanthanides and 5d elements.
Sample Practice Questions
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Which group of elements has the general valence configuration ns²np⁶?
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Answer: Group 18 (Noble gases)
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Which period contains elements with 4f electrons being filled?
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Answer: Period 6 (lanthanides)
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d-block elements are called transition metals because they:
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Answer: Have partially filled d orbitals in atoms or ions
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Electron affinity is highest (most negative) for:
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Answer: Cl
Practice Questions
Practice 20 randomly selected NEET questions on Periodic Table & p-Block Elements. Answers are revealed after each question.
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