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What is the radius of iodine atom? (atomic no. 53, mass no. 126)

A

2.5 × 10⁻¹¹ m

B

2.5 × 10⁻⁹ m

C

7 × 10⁻⁹ m

D

7 × 10⁻⁶ m

Step-by-Step Solution

  1. Atomic Radius: The atomic radius of an iodine atom is approximately 133 \pm (1.33×10101.33 \times 10^{-10} m) .
  2. Nuclear Radius: The radius of a nucleus is calculated using R=R0A1/3R = R_0 A^{1/3}, where R01.1×1015R_0 \approx 1.1 \times 10^{-15} m and AA is the mass number. For Iodine-126: R1.1×1015×(126)1/31.1×5×10155.5×1015R \approx 1.1 \times 10^{-15} \times (126)^{1/3} \approx 1.1 \times 5 \times 10^{-15} \approx 5.5 \times 10^{-15} m .
  3. Discrepancy: The provided probable answer (2.5×10112.5 \times 10^{-11} m) does not match the standard atomic radius (1.3×1010\sim 1.3 \times 10^{-10} m) or the nuclear radius (5.5×1015\sim 5.5 \times 10^{-15} m). It is significantly smaller than the atomic radius and much larger than the nuclear radius. The question might refer to a specific context not fully captured or contains a data error.
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