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2. structure of atom — Chemistry STD 11 Science — Question

Gujarat BoardEnglish MediumSTD 11 ScienceChemistry2. structure of atom1 Mark
MCQ
Which of the following pair is not isoelectronic species? (At. no. $Sm , 62 ; Er , 68: Yb , 70: Lu , 71 ; Eu , 63: Tb$, $65$; $\operatorname{Tm}, 69)$
  • A
    $Sm ^{2+}$ and $Er ^{3+}$
  • B
    $Yb ^{2+}$ and $Lu ^{3+}$
  • C
    $Tb ^{2+}$ and $Tm ^{4+}$
  • ✓
    both $(A)$ and $(C)$ are true
✓

Answer

Correct option: D.
both $(A)$ and $(C)$ are true
d
$Sm ^{2+} \rightarrow$ electron $=60$

$Er ^{3+} \rightarrow$ electron $=65$

$Tb ^{2+} \rightarrow$ electron $=63$

$Tm ^{4+} \rightarrow$ electron $=65$

all are $(not\,isoelectronic)$

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