S-Block Elements Revision - JEE Advanced Level
The S-block elements of the periodic table, consisting of Group 1 (alkali metals) and Group 2 (alkaline earth metals), are characterized by their distinct physical and chemical properties. Understanding their properties, trends, and reactions is crucial for JEE Advanced preparation. For a revision of the periodic table trends, check our Periodic Table Revision Series.
1. Key Properties and Trends of S-Block Elements
S-block elements exhibit properties such as low ionization energies, high reactivity, and formation of ionic compounds. Some important trends include:
| Property | Group 1 (Alkali Metals) | Group 2 (Alkaline Earth Metals) |
|---|---|---|
| Atomic Radius | Increases down the group | Increases down the group |
| Ionization Energy | Decreases down the group | Decreases down the group |
| Electronegativity | Decreases down the group | Decreases down the group |
| Melting and Boiling Points | Decrease down the group | Decrease down the group |
2. Important Reactions of S-Block Elements
The following table summarizes some key reactions involving S-block elements:
| Reaction Type | Example | Description |
|---|---|---|
| Reaction with Water | 2Na + 2H2O → 2NaOH + H2↑ | Alkali metals react vigorously with water to form hydroxides and hydrogen gas. |
| Formation of Oxides | 2Mg + O2 → 2MgO | Alkaline earth metals form oxides when heated in oxygen. |
| Reaction with Halogens | 2K + Cl2 → 2KCl | Alkali metals react with halogens to form ionic halides. |
| Formation of Carbonates | CaO + CO2 → CaCO3 | Alkaline earth metals react with carbon dioxide to form carbonates. |
3. Interactive Example: Reactivity of Alkali Metals with Water
Select an alkali metal to see its reactivity with water:
Example Quiz: Which alkali metal is the most reactive with water?
4. Conclusion
Revising the properties and reactions of S-block elements is crucial for JEE Advanced. Ensure you understand the underlying concepts and practice different types of problems for a comprehensive understanding.
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