JEE Main 2003 — Structure Of Atom Question with Solution
From: AIEEE 2003
Question
Which one of the following groupings represents a collection of isoelectronic species? (At. nos. : Cs : 55, Br : 35)
Choose an option
Show full solutionCorrect option: A
Correct answer
AN3-, F-, Na+
Step-by-step explanation
Isoelectronic means those species whose electron number are same.
N3-, F-, Na+
| Species | Atomic Number | Electron Number |
|---|---|---|
| N3- | 7 | 7 + 3 = 10 |
| F- | 9 | 9 + 1 = 10 |
| Na+ | 11 | 11 - 1 = 10 |
| Be | 4 | 4 |
| Al3+ | 13 | 13 - 3 = 10 |
| Cl- | 17 | 17 + 1 = 8 |
| Ca2+ | 20 | 20 - 2 = 18 |
| Cs+ | 55 | 55 - 1 = 54 |
| Br | 35 | 35 |
| Mg2+ | 12 | 12 -2 = 10 |
N3-, F-, Na+
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This is a previous-year question from JEE Main 2003, covering the Structure Of Atom chapter of Chemistry. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.