Which of the Following Are Isoelectronic Species I.E., Those Having the Same Number of Electrons? - Chemistry

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Answer in Brief

Which of the following are isoelectronic species i.e., those having the same number of electrons?

Na+, K+, Mg2+, Ca2+, S2–, Ar

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Solution

Isoelectronic species have the same number of electrons.

Number of electrons in sodium (Na) = 11

Number of electrons in (Na+) = 10

A positive charge denotes the loss of an electron.

Similarly,

Number of electrons in K+ = 18

Number of electrons in Mg2+ = 10

Number of electrons in Ca2+ = 18

A negative charge denotes the gain of an electron by a species.

Number of electrons in sulphur (S) = 16

∴ Number of electrons in S2- = 18

Number of electrons in argon (Ar) = 18

Hence, the following are isoelectronic species:

1) Na+ and Mg2+ (10 electrons each)

2) K+, Ca2+, S2– and Ar (18 electrons each)

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Chapter 2: Structure of Atom - EXERCISES [Page 70]

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NCERT Chemistry Part 1 and 2 Class 11
Chapter 2 Structure of Atom
EXERCISES | Q 2.22 | Page 70

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