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Physics

Atoms

A Physics chapter of the NEET syllabus, and how to practise it for the computer-based exam.

Exam rules change between cycles. Confirm dates, syllabus and pattern against NTA's official site. We are not NTA.

Weightage: what the paper actually did

Atoms carried 3 questions in the NEET 2026 paper. One paper is a data point, not a destiny: NTA moves weight between chapters every cycle, which is why the weightage tables deserve care. The stable facts are the paper's shape: 180 questions, 720 marks, +4 right, −1 wrong.

Sample PYQs from this chapter

Real questions NTA asked from Atoms, with the answer and the working. Try before you peek.

Question 1 · NEET 2026

In the first excited state of hydrogen atom, the energy of its electron is −3.4-3.4 eV. The radial distance of the electron from the hydrogen nucleus in this case is approximately: (Take 1 eV = 1.6×10−191.6 \times 10^{-19} J, e = 1.6×10−191.6 \times 10^{-19} C and 14πε0=9×109\frac{1}{4\pi\varepsilon_0} = 9 \times 10^{9} N m2^2/C2^2)
  1. A.2.1×10−92.1 \times 10^{-9} m
  2. B.2.1×10−82.1 \times 10^{-8} m
  3. C.2.1×10−102.1 \times 10^{-10} m
  4. D.2.1×10−112.1 \times 10^{-11} m
Answer and explanation

Answer: C

For the hydrogen atom the magnitude of the total energy equals half the magnitude of the potential energy, so KQ22r=3.4\frac{KQ^2}{2r} = 3.4 eV. Solving, r=9×109×(1.6×10−19)22×3.4×1.6×10−19≈2.1×10−10r = \frac{9\times10^{9}\times(1.6\times10^{-19})^2}{2\times3.4\times1.6\times10^{-19}} \approx 2.1\times10^{-10} m, option (3). This is the n=2n=2 Bohr orbit radius, i.e. 4a0≈2.14a_0 \approx 2.1 angstrom.

Question 2 · NEET 2020

For which one of the following, Bohr model is not valid ?
  1. A.Singly ionised helium atom (He+)
  2. B.Deuteron atom
  3. C.Singly ionised neon atom (Ne+)
  4. D.Hydrogen atom
Answer and explanation

Answer: C

The Bohr model is valid for hydrogen-like atoms, which have one electron. Hydrogen, singly ionised helium, and deuteron all fit this criterion. Singly ionised neon, however, has more than one electron, making the Bohr model inapplicable. Chapter: Atoms.

How to practise Atoms

Chapter by chapter, against real past-paper questions, on a screen: NEET is computer based from 2027. Read the chapter once, then attempt its PYQs until your accuracy stops climbing, and let the wrong answers tell you which lines to reread. If the chapter keeps refusing to stick, that has its own guide. There is also a free NEET mini mock with answers.

Nearby Physics chapters

Questions

How many questions did Atoms have in NEET 2026?

Atoms carried 3 questions in the NEET 2026 paper. Weightage shifts between cycles, so treat it as a probability, not a promise.

Where can I practise Atoms PYQs for NEET?

Explore available chapter-wise NEET practice in BrainIt, free until the 2027 exam. Review explanations and track chapter accuracy to guide your revision. Sample questions from this chapter are on this page.

Is Atoms important for NEET 2027?

It is part of the Physics syllabus the paper draws from, and NEET 2027 is computer based, so practise it on a screen. Your own accuracy in the chapter matters more than any weightage table: a heavy chapter you already score well on needs less time than a light one you keep missing.

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