Given below are two statements: Statement I: The radii of isoelectronic species increases in the order: Mg2+ < Na+ < F-…

🧠 Two facts to verify: isoelectronic size order, and the Cl-beats-F anomaly in halogen EGE Both statements involve standard NCERT facts. Isoelectronic species: more protons → smaller ion. Halogen EGE: F is anomalously LESS exothermic than Cl because F's tiny $2p$ shell repels the incoming electron.

🗺️ Check Statement I — isoelectronic radii $\ce{Mg^{2+}}$ ($Z=12$), $\ce{Na^+}$ ($Z=11$), $\ce{F^-}$ ($Z=9$), $\ce{O^{2-}}$ ($Z=8$). All have 10 electrons. Higher Z = stronger nuclear pull = smaller ion. So increasing size order = decreasing Z order: $\ce{Mg^{2+} < Na^+ < F^- < O^{2-}}$. Matches Statement I exactly. True.

Check Statement II — halogen EGE magnitudes Pauling values (kJ/mol): $\ce{Cl} = -349$, $\ce{F} = -328$, $\ce{Br} = -325$, $\ce{I} = -295$. By magnitude (most negative = greatest): $\ce{Cl > F > Br > I}$. Matches Statement II exactly. True.

Both statements are correct.

⚠️ Common mistake Many students reject Statement II thinking "F is the smallest halogen, so F should have the most negative EGE." The trap is to assume the simple group trend. F's compact $2p$ orbital makes the incoming electron face heavy repulsion, so Cl beats F here. Memorize this exception: $|EGE(\ce{Cl})| > |EGE(\ce{F})|$ — always.

$\boxed{\text{Answer: (d)}}$