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Chemistry · PYQ NEET UG 2025
हिन्दीWhich of the following statements are true? A. Unlike Ga that has a very high melting point, Cs has a very low melting point. B. On Pauling scale, the electronegativity values of N and Cl are not the same. C. \( \text{Ar}, \text{K}^+, \text{Cl}^-, \text{Ca}^{2+}, \) and \( \text{S}^{2-} \) are all isoelectronic species. D. The correct order of the first ionization enthalpies of Na, Mg, Al, and Si is \( \text{Si} > \text{Al} > \text{Mg} > \text{Na} \).\nE. The atomic radius of Cs is greater than that of Li and Rb. Choose the correct answer from the options given below :
Correct answer · Option 4
A, C, and E only
Explanation
Statements A (Ga melts at 30°C, Cs at 28.5°C both low, but Ga is unique), C (all have 18 electrons), and E (radius increases down group) are correct. First ionization energy order is \( \text{Si} > \text{Mg} > \text{Al} > \text{Na} \), making D false.
