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Chemistry

Structure of Atom

A Chemistry 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

Structure of Atom 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 Structure of Atom, with the answer and the working. Try before you peek.

Question 1 · NEET 2020

The number of protons, neutrons and electrons in 1^{1}7^{7}5^{5}7_{7}1_{1}Lu, respectively, are
  1. A.104, 71 and 71
  2. B.71, 71 and 104
  3. C.175, 104 and 71
  4. D.71, 104 and 71
Answer and explanation

Answer: D

The atomic number (71) gives the number of protons and electrons, and the mass number (175) minus the atomic number gives the number of neutrons: 175 - 71 = 104. Chapter: Structure of Atom.

Question 2 · NEET 2026

A bulb is rated at 150 watt, converting 8% energy into light. If energy of one photon is 4.42×10−19 J4.42 \times 10^{-19}\ \text{J}, how many photons are emitted by the bulb per second?
  1. A.2.71×10192.71 \times 10^{19}
  2. B.4.06×10194.06 \times 10^{19}
  3. C.27.2×101927.2 \times 10^{19}
  4. D.1.35×10191.35 \times 10^{19}
Answer and explanation

Answer: A

In one second the bulb consumes 150 J; only 8% becomes light, so light energy per second = 150 * 0.08 = 12 J. The number of photons n = (light energy)/(energy per photon) = 12 / (4.42 * 10−1910^{-19}) ≈\approx 2.71 * 101910^{19}. The other options come from omitting the 8% factor or arithmetic errors.

How to practise Structure of Atom

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 Chemistry chapters

Questions

How many questions did Structure of Atom have in NEET 2026?

Structure of Atom 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 Structure of Atom 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 Structure of Atom important for NEET 2027?

It is part of the Chemistry 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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