Among the following, number of sets of species having same number of total electrons and correct order of ionisation energy is
(I) $Be > B^{+}$ (II) $N < O^{+}$
(III) $Na^{+} > Ne$ (IV) $H < He^{+}$
(v) $F^{-} < Cl^{-}$

Question

Among the following, number of sets of species having same number of total electrons and correct order of ionisation energy is

(I) $Be > B^{+}$ (II) $N < O^{+}$

(III) $Na^{+} > Ne$ (IV) $H < He^{+}$

(v) $F^{-} < Cl^{-}$

TestHub · Accepted Answer

(i) Be & B⁺ → same electrons (4), IE: Be > B⁺ (Correct)

(ii) N & O⁺ → same electrons (7), actual: N > O⁺, so given is wrong

(iii) Na⁺ & Ne → same electrons (10), Na⁺ > Ne (correct)

(iv) H & He⁺ → same electrons (1), H < He⁺ (correct)

(v) F⁻ & Cl → same electrons (10), actual: F⁻ > Cl, so given (wrong )

Correct sets = 3

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