Alkali metal from the following with least melting point is:
- Rb
- Na
- K
- Cs
The Correct Option is D
Solution and Explanation
The melting points of alkali metals decrease down the group. This trend is explained by the nature of metallic bonding:
- Metallic bonding arises from the electrostatic attraction between the positive metal ions and the sea of delocalized electrons.
- As the atomic size increases down the group, the outermost electron is held less strongly.
- This leads to weaker metallic bonding and, consequently, a lower melting point.
Melting Points of the Given Alkali Metals:
- Sodium (Na): 98°C
- Potassium (K): 64°C
- Rubidium (Rb): 39°C
- Cesium (Cs): 29°C
Observation:
Among the given alkali metals, cesium (Cs) is the largest atom, leading to the weakest metallic bonding and the lowest melting point.
Conclusion:
Final Answer: Cs has the least melting point.
Top JEE Main Chemistry Questions
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)- At equilibrium the concentrations of and in a sealed vessel at . What will be for the reaction
- Find out the major products from the following reactions
Cobalt chloride when dissolved in water forms pink colored complex $X$ which has octahedral geometry. This solution on treating with cone $HCl$ forms deep blue complex, $\underline{Y}$ which has a $\underline{Z}$ geometry $X, Y$ and $Z$, respectively, are
- The correct order of atomic radii is:
Top JEE Main Questions
- In a hydrogen like atom, when an electron jumps from the $M$ - shell to the $L$ - shell, the wavelength of emitted radiation is $\lambda$. If an electron jumps from $N$-shell to the $L$-shell, the wavelength of emitted radiation will be :
- Two masses $m$ and $\frac{m}{2}$ are connected at the two ends of a massless rigid rod of length $l$. The rod is suspended by a thin wire of torsional constant $k$ at the centre of mass of the rod-mass system(see figure). Because of torsional constant $k$, the restoring torque is $\tau =k\theta$ for angular displacement $\theta$. If the rod is rota ted by $\theta_0$ and released, the tension in it when it passes through its mean position will be:
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)- The value of is
- The number of terms of an is even. The sum of the odd terms is and of the even terms is . The last term exceeds the first by . Then the number of terms in the series is ______.