Class 12th Chemistry-Periodic Classification Of Elements And Periodicity

Full Chapter Notes

Short Question

MCQ’s with Exercise

Class 12th Chemistry Chapter – “Periodic Classification of Elements and Periodicity” explores the organization of elements based on their properties and the trends observed in the periodic table. Here’s a concise overview:

1. History of Periodic Classification: Discusses early attempts at classification by scientists like Dobereiner, Newlands, and Mendeleev, leading to the modern periodic table.
2. Modern Periodic Table: Introduces the layout of the modern periodic table, including groups (columns) and periods (rows), and how elements are arranged based on increasing atomic number.
3. Periodic Trends: Examines trends in properties such as atomic radius, ionization energy, electron affinity, and electronegativity across periods and down groups:
   • Atomic Radius: Generally decreases across a period and increases down a group.
   • Ionization Energy: Increases across a period and decreases down a group.
   • Electron Affinity: Shows varied trends but generally becomes more negative across a period.
   • Electronegativity: Increases across a period and decreases down a group.
4. Classification of Elements: Discusses the classification into metals, non-metals, and metalloids, along with their characteristic properties.
5. Importance of Periodicity: Explains how periodic trends help predict the behavior and reactivity of elements, aiding in the understanding of chemical bonding and reactions.

This chapter provides a foundational understanding of how elements are classified and the periodic trends that influence their properties, essential for further studies in chemistry.