NEET UG 2014 — Chemistry Inorganic Chemistry

2014mcqeasy

Which of the following orders of ionic radii is correctly represented?

Official previous-year question

Held on 30 Apr 2014 · Verified 9 Jul 2026.

Options

A
${H}^{-}>{H}^{+}>H$
B
$N{a}^{+}>{F}^{-}>{O}^{2-}$
C
F->O2-->Na+
D
${\mathrm{Al}}^{3+}>{\mathrm{Mg}}^{2+}>{N}^{3-}$

Did you get this right?

Solution

Isoelectronic species refers to two atoms, ions or molecules that have the same electronic structure.

For isoelectronic species, ionic radii decrease with increase in nuclear charge (i.e., no. of protons). Thus, the cation with greater $+\mathrm{ve}$ charge will have a smaller radius and the anion with greater $-\mathrm{ve}$ charge will have a larger radius.

${\mathrm{Na}}^{+},{F}^{-},{O}^{-2},{\mathrm{Al}}^{3+},{\mathrm{Mg}}^{2+}\mathrm{and}{N}^{3-}$ are isoelectronic. Hence, the order of their ionic radius is

${N}^{3-}>{O}^{2-}>{F}^{-}>{\mathrm{Na}}^{+}>{\mathrm{Mg}}^{2+}>{\mathrm{Al}}^{3+}$ .

For an atom, the cation is smaller than both neutral atom and anion.

Then correct size order for hydrogen, proton and hydride ion is

${H}^{-}>H>{H}^{+}$

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NEET UG 2014 — Chemistry Inorganic Chemistry

2014mcqeasy

Which of the following orders of ionic radii is correctly represented?

Official previous-year question

Held on 30 Apr 2014 · Verified 9 Jul 2026.

Options

A
${H}^{-}>{H}^{+}>H$
B
$N{a}^{+}>{F}^{-}>{O}^{2-}$
C
F->O2-->Na+
D
${\mathrm{Al}}^{3+}>{\mathrm{Mg}}^{2+}>{N}^{3-}$

Did you get this right?

Solution

Isoelectronic species refers to two atoms, ions or molecules that have the same electronic structure.

${\mathrm{Na}}^{+},{F}^{-},{O}^{-2},{\mathrm{Al}}^{3+},{\mathrm{Mg}}^{2+}\mathrm{and}{N}^{3-}$ are isoelectronic. Hence, the order of their ionic radius is

${N}^{3-}>{O}^{2-}>{F}^{-}>{\mathrm{Na}}^{+}>{\mathrm{Mg}}^{2+}>{\mathrm{Al}}^{3+}$ .

For an atom, the cation is smaller than both neutral atom and anion.

Then correct size order for hydrogen, proton and hydride ion is

${H}^{-}>H>{H}^{+}$

Your note

NEET UG Inorganic Chemistry in other years

Keep practicing Inorganic Chemistry

Work through every NEET UG Inorganic Chemistry PYQ, year by year.

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NEET UG 2014 — Chemistry Inorganic Chemistry

Options

Did you get this right?

Solution

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NEET UG Inorganic Chemistry in other years

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Physical Chemistry

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NEET UG 2014 — Chemistry Inorganic Chemistry

Options

Did you get this right?

Solution

Your note

NEET UG Inorganic Chemistry in other years

More NEET UG Inorganic Chemistry questions

Other Chemistry topics for NEET UG

Physical Chemistry

Organic Chemistry

Keep practicing Inorganic Chemistry