back to directory
NEET PHYSICSNUCLEIHard

Question

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 (1.33×10−101.33 \times 10^{-10} m) .
  2. Nuclear Radius: The radius of a nucleus is calculated using R=R0A1/3R = R_0 A^{1/3}, where R0≈1.1×10−15R_0 \approx 1.1 \times 10^{-15} m and AA is the mass number. For Iodine-126: R≈1.1×10−15×(126)1/3≈1.1×5×10−15≈5.5×10−15R \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 (2.5×10−112.5 \times 10^{-11} m) does not match the standard atomic radius (∼1.3×10−10\sim 1.3 \times 10^{-10} m) or the nuclear radius (∼5.5×10−15\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.

Exam Context & Concepts Covered

This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from NUCLEI. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

PHYSICSNUCLEIradiusiodineatomic

More NUCLEI Questions

View all

In the nuclear reaction $X(n, \alpha){}_{3}^{7}\mathrm{Li}$, the term $X$ will be:

A.${}_{5}^{10}\mathrm{B}$
B.${}_{5}^{9}\mathrm{B}$
C.${}_{5}^{11}\mathrm{B}$
D.${}_{2}^{4}\mathrm{He}$
EasySolve

The half-life of a radioactive sample undergoing $\alpha$-decay is $1.4 \times 10^{17}\text{ s}$. If the number of nuclei in the sample is $2.0 \times 10^{21}$, the activity of the sample is nearly equal to:

A.$10^4\text{ Bq}$
B.$10^5\text{ Bq}$
C.$10^6\text{ Bq}$
D.$10^3\text{ Bq}$
MediumSolve

If the nuclear radius of $^{27}\text{Al}$ is 3.6 Fermi, the approximate nuclear radius of $^{64}\text{Cu}$ in Fermi is:

A.2.4
B.1.2
C.4.8
D.3.6
MediumSolve

The half-life of a radioactive substance is 30 minutes. The time (in minute) taken between 40% decay and 85% decay of the same radioactive substance is:

A.15
B.30
C.45
D.60
MediumSolve

The fraction of the original number of radioactive atoms that disintegrates (decays) during the average lifetime of a radioactive substance will be:

A.1/e
B.1/(1+e)
C.(e-1)/(e+1)
D.(e-1)/e
MediumSolve

A nucleus of mass number 189 splits into two nuclei having mass numbers 125 and 64. The ratio of the radius of two daughter nuclei respectively is:

A.25:16:00
B.1:1
C.4:5
D.5:4
EasySolve

In the nuclear emission stated above: ${}_{82}^{290}X \xrightarrow{\alpha} Y \xrightarrow{e^+} Z \xrightarrow{\beta^-} P \xrightarrow{e^-} Q$, the mass number and atomic number of the product Q respectively, are:

A.286, 80
B.288, 82
C.286, 81
D.280, 81
MediumSolve

The energy equivalent of 0.5 g of a substance is:

A.4.5 × 10^{13} J
B.1.5 × 10^{13} J
C.0.5 × 10^{13} J
D.4.5 × 10^{16} J
EasySolve

Why 32,000+ students choose TopperSquare

Everything you need to crack NEET

15,000+ Chapter MCQs

Physics, Chemistry, Biology — chapter-wise, topic-wise practice

AI Performance Analytics

Know your weak topics. Get a personalised study plan.

Full NEET Mock Tests

180 questions, timed, with detailed score analysis

PYQ Sets 2010–2024

15 years of past papers with solved explanations

Start Practising Free

No credit card · 30-second signup · Free forever plan included

This neet physics practice question is part of the TopperSquare free question bank. TopperSquare offers 15,000+ chapter-wise NEET MCQs across Physics, Chemistry, and Biology with detailed step-by-step explanations, full mock tests, NEET PYQs (2010–2024), and an AI-powered performance analytics dashboard. browse all neet practice questions → · practice physics sets →

Explore more subjects:Physics MCQs•Chemistry MCQs•Biology MCQs•Botany MCQs•Zoology MCQs•NEET Mock Tests•NEET PYQs