Given below are two statements: Statement I: The correct order of first ionization enthalpy values of Li, Na, F and Cl is $$Na < Li < Cl < F$$. Statement II: The correct order of negative electron gain enthalpy values of Li, Na, F and Cl is $$Na < Li < F < Cl$$. In the light of the above statements, choose the correct answer from the options given below:

We need to verify two statements about ionization enthalpy and electron gain enthalpy.

• Na: 496 kJ/mol
• Li: 520 kJ/mol
• Cl: 1251 kJ/mol
• F: 1681 kJ/mol

Order: Na (496) < Li (520) < Cl (1251) < F (1681) ✓

Statement I is TRUE.

Negative electron gain enthalpy means how exothermic the process of gaining an electron is. A more negative ΔH_eg means a higher tendency to gain an electron.

• Na: −53 kJ/mol
• Li: −60 kJ/mol
• F: −328 kJ/mol
• Cl: −349 kJ/mol

Order of negative electron gain enthalpy (magnitude): Na (53) < Li (60) < F (328) < Cl (349) ✓

Statement II is TRUE.

Note: Chlorine has a more negative electron gain enthalpy than fluorine because fluorine's very small size causes high electron-electron repulsion in its compact 2p orbitals.

The answer is Option D: Both Statement I and Statement II are true.