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Structure of Atom — Chemistry STD 11 Science — Question

Maharashtra BoardEnglish MediumSTD 11 ScienceChemistryStructure of Atom1 Mark
MCQ
Calculate radius of third orbit of $He ^*$.
  • A
    $52.9 pm$
  • B
    $105.8 pm$
  • ✓
    $238.1 pm$
  • D
    $423.2 pm$
✓

Answer

Correct option: C.
$238.1 pm$
(c) $: r_n=\frac{n^2}{Z} \times 0.529 A$
$
r_3=\frac{3^2}{2} \times 0.529 A \Rightarrow r_3=238.1 pm
$

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