Question

The metal having low melting point is

• A. Li
• B. Cs
• C. In
• D. Pb

Hint:

Cesium, a Group-1 alkali metal, has a very low melting point: ~28.5°C.

Answer 1

The Correct Option is B

Among the options: - Li (Lithium) → Melting point: ~180°C
- Cs (Cesium) → Melting point: ~28.5°C
- In (Indium) → Melting point: ~157°C
- Pb (Lead) → Melting point: ~327°C
Clearly, Cesium (Cs) has the lowest melting point among all — it can melt almost at room temperature.

Answer 2

Step 1: Understanding the Melting Point of Metals
Melting point is the temperature at which a substance changes from solid to liquid. In metals, the melting point is influenced by the strength of metallic bonding. Stronger metallic bonds (more delocalized electrons and closer-packed atoms) result in higher melting points, while weaker metallic bonds result in lower melting points.

Step 2: Position of Cesium (Cs) in the Periodic Table
Cesium (Cs) is an alkali metal and belongs to Group 1 of the periodic table. Alkali metals are characterized by having one valence electron and are highly reactive. As we move down the group from lithium (Li) to cesium (Cs), the atomic size increases and the metallic bonding becomes weaker due to greater distance between the nucleus and the valence electron. This leads to a decrease in melting point.

Step 3: Melting Point of Cesium
Cesium has one of the lowest melting points among all metals, approximately 28.5°C. This is because its large atomic size and weak metallic bonding make it easy for the atoms to break free from the solid structure. In fact, cesium can melt just above room temperature, which is unusual for a metal.

Step 4: Final Conclusion
Among metals, cesium (Cs) has a notably low melting point due to its large atomic radius and weak metallic bonds. This makes it the correct answer when identifying the metal with the lowest melting point among commonly studied elements.