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प्रश्न
Which of the alkali metal is having least melting point?
विकल्प
Na
K
Rb
Cs
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उत्तर
Cs
Explanation:
Atomic size increases as we move down the alkali group. As a result, the binding energies of their atoms in the crystal lattice decrease. Also, the strength of metallic bonds decreases on moving down a group in the periodic table. This causes a decrease in the melting point. Among the given metals, Cs is the largest and has the least melting point.
संबंधित प्रश्न
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(i) Blue solution was obtained initially.
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The ease of absorption of the hydrated alkali metals ions in an ion-exchange resin follows the order:
Match List-I with List-II.
| List-I | List-II |
| (Metal) | (Emitted light wavelength (nm)) |
| (a) Li | (I) 780.0 |
| (b) Na | (II) 455.5 |
| (c) Rb | (III) 670.8 |
| (d) Cs | (IV) 589.2 |
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Reason (R) : Lithium has higher polarising power than other alkali metal group members.
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