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

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Correct answer: 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.

Given below are two statements: Statement I : The second ionisation...

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