Chapter 3 of Class 11 Chemistry, titled Classification of Elements and Periodicity in Properties, explains how elements are arranged in a systematic way based on their properties. It talks about the development of the periodic table, types of elements, periodic trends like atomic size, ionisation energy, electronegativity, and more. This chapter forms the base of understanding the periodic table and how properties of elements change in groups and periods.
I decided to write on this chapter because the periodic table is like the backbone of chemistry. Whether you’re preparing for boards or entrance exams like NEET or JEE, understanding trends across the periodic table helps you solve problems quickly and logically. I’ve seen many students mug up periodic trends without knowing why they exist. This chapter doesn’t just give facts – it teaches the logic behind them. Personally, I started loving chemistry once I understood the periodic table properly. That’s why I want to help students see the full picture through this post, and I’ve also added a direct PDF download link so you can access the original NCERT text for reference.
Key Topics Covered in Chapter 3
Let’s go through the main points you’ll learn in this chapter:
1. Need for Classification of Elements
- Early attempts to classify elements
- Limitations of Dobereiner’s Triads and Newlands’ Octaves
- Mendeleev’s Periodic Law
- Modern Periodic Law: Properties of elements are periodic functions of their atomic numbers
2. Modern Periodic Table
- Structure and format
- Periods and groups
- Types of elements: s-block, p-block, d-block, f-block
- Metals, non-metals, and metalloids
3. Nomenclature of Elements with Atomic Number >100
- Systematic naming of elements using Latin roots
4. Electronic Configuration and Periodicity
- Relation between electronic configuration and position in the periodic table
- Periodic properties and their trends
