JEE Main 2004 — Structure Of Atom Question with Solution
From: AIEEE 2004
Question
Which one of the following sets of ions represents the collection of isoelectronic species? (Atomic nos. : F = 9, Cl = 17, Na = 11, Mg = 12, Al = 13, K = 19, Ca = 20, Sc = 21)
Choose an option
Show full solutionCorrect option: C
Correct answer
CK+, Ca2+, Sc3+, Cl-
Step-by-step explanation
Isoelectronic means those species whose no of electrons are same.
So, option is correct.
| Ions | Atomic No | No of Electron |
|---|---|---|
| K+ | 19 | 19-1=18 |
| Ca+2 | 20 | 20-2=18 |
| Sc+3 | 21 | 21-3=18 |
| Cl- | 17 | 17+1=18 |
So, option is correct.
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This is a previous-year question from JEE Main 2004, 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.