The species $F X^{-}$ , $Ne$ , $Na X^{+}$ and $Mg X^{2 +}$ are isoelectronic. The correct order of the enthalpy needed to remove one electron from each is

A $Ne < F X^{-} < Na X^{+} < Mg X^{2 +}$
B $Na X^{+} < Mg X^{2 +} < F X^{-} < Ne$
C $F X^{-} < Ne < Na X^{+} < Mg X^{2 +}$
D $Mg X^{2 +} < Na X^{+} < Ne < F X^{-}$

Answer: C

With the same 10 electrons, a larger nuclear charge pulls the electrons more strongly and shrinks the ion. Nuclear charges are 9, 10, 11, 12, so the electron removal enthalpy increases in the order

F X^{-} < Ne < Na X^{+} < Mg X^{2 +}

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The species FX−, Ne, NaX+ and MgX2+ are isoelectronic. The correct order of the enthalpy needed to remove one electron from each is

Answer: C

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The species $F X^{-}$ , $Ne$ , $Na X^{+}$ and $Mg X^{2 +}$ are isoelectronic. The correct order of the enthalpy needed to remove one electron from each is