Gujarat BoardEnglish MediumSTD 9ScienceStructure of the Atom1 Mark
MCQ
The electronic configuration of $\mathrm{Cl}^{-}$ ion is:
A
$2, 8, 7$
✓
$2, 8, 8$
C
$2, 8, 6$
D
$2, 8, 8, 1$
✓
Answer
Correct option: B.
$2, 8, 8$
Chlorine atom $(Cl)$ has atomic number $17$. It contains $17$ protons and $17$ electrons.
Chlorine ion ($\mathrm{Cl}^{-}$) is formed when $Cl$ gains one electron.
So, $\mathrm{Cl}^{-}$ has $18$ electrons and $17$ protons.
Therefore, the electronic configuration of $\mathrm{Cl}^{-} = 2, 8, 8.$
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