Class 11 Chemistry Chapter 3 Classification of Elements and Periodicity in Properties – Revision Notes

Quick revision notes for Class 11 Chemistry Chapter 3 (Classification of Elements and Periodicity in Properties). These Class 11 Chemistry Chapter 3 notes are ideal for quick revision just before exams.

History

• Doebereiner → Newlands → Mendeleev → Modern periodic law (Moseley, atomic number).

Structure

• 18 groups, 7 periods; s, p, d, f blocks.

Periodic Trends

• Atomic radius: decreases across period, increases down group.
• Ionization enthalpy: increases across period, decreases down group.
• Electronegativity: increases across period, decreases down group.

One-Line Summary

The modern periodic table organizes elements by atomic number, revealing periodic trends in atomic radius, ionization enthalpy, electron gain enthalpy, and electronegativity across periods and groups.

Written by Satish

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