Which 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. \(Ar, K^+, Cl^-, Ca^{2+}\) and \(S^{2-}\) are all isoelectronic species.
D. The correct order of the first ionization enthalpies of Na, Mg, Al, and Si is Si > Al > Mg > Na
E. The atomic radius of Cs is greater than that of Li and Rb.
Choose the correct answer from the options given below:
1. C and D only
2. A, C and E only
3. A, B and E only
4. C and E only
Subtopic:  Ionization Energy (IE) | Electronegativity |
Level 3: 35%-60%
NEET - 2025
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Please attempt this question first.

Which one of the following represents all isoelectronic species?
1. \(\mathrm{Na^+ , Cl^-, O^- , NO^+}\) 2. \(\mathrm{N_2O, N_2O_4 , NO^+, NO}\)
3. \(\mathrm{Na^+ , Mg^{2+} , O^- , F^-}\) 4. \(\mathrm{Ca^{2+} , Ar, K^+, Cl^-}\)
Subtopic:  Ionization Energy (IE) |
 77%
Level 2: 60%+
NEET - 2023
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The first ionization enthalpies of elements X and Y are 419 kJ mol–1 and 590 kJ mol–1, respectively and the second ionization enthalpies of X and Y are 3069 kJ mol–1 and 1145 kJ mol–1, respectively. The correct statement is:
1. X is an alkali metal and Y is an alkaline earth metal.
2. X is an alkaline earth metal and Y is an alkali metal.
3. Both X and Y are alkali metals.
4. Both X and Y are alkaline earth metals.
Subtopic:  Ionization Energy (IE) |
 72%
Level 2: 60%+
NEET - 2022
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