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Question: Answered & Verified by Expert
The radius of the first orbit of hydrogen atom is 0.52×10-8 cm. The radius of the first orbit of helium atom is
ChemistryStructure of AtomJEE Main
Options:
  • A 0.26×10-8 cm
  • B 0.52×10-8 cm
  • C 1.04×10-8 cm
  • D 2.08×10-8 cm
Solution:
2068 Upvotes Verified Answer
The correct answer is: 0.26×10-8 cm
rn=n2Z0.52×10-8cm
For H-atom Z=1 , n = 1, r1=0.52×10-8cm
For He atom, n = 1, Z = 2,
r1=12×0.5×10-8 cm
=0.26×10-8 cm

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