Given below are two statements: Statement I : The second ionisation enthalpy of Na is larger than the corresponding ionisation enthalpy of Mg. Statement II : The ionic radius of O ^ 2- is larger than that of F ^ - . In the light of the above statements, choose the correct answer from the options given below
D. Both Statement I and Statement II are true
Statement I examines second ionization enthalpy: Na (1s^2 2s^2 2p^6 3s^1) loses its first electron to achieve a stable noble gas configuration. The second ionization would break into the 2p core, requiring enormous energy. Mg (1s^2 2s^2 2p^6 3s^2) loses its second electron from the 3s orbital, which is less stable. Thus, IE_2 of Na is much larger than IE_2 of Mg. Statement I is TRUE. Statement II compares O^ 2- and F^-: both are isoelectronic with 10 electrons. O^ 2- has 8 protons while F^- has 9 protons. The lower nuclear charge in O^ 2- results in weaker electrostatic attraction, making the ionic radius of O^ 2- larger than F^-. Statement II is TRUE.
Related: Chemistry — Classification of Elements and Periodicity in Properties · All PYQ Banks