Skip to main content
Super TutorResources
Chapter 2 of 9
QuestionsNotesFlashcardsSummaryFormulasQuizConceptsSyllabusPlan
Important Questions

Structure of Atom

ICSE · Class 11 · Chemistry

Most important questions from Structure of Atom for ICSE Class 11 Chemistry board exam 2026. MCQs, short answer, and long answer questions with marks.

89 questions56 flashcards5 concepts

Interactive on Super Tutor

Studying Structure of Atom? Get the full interactive chapter.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan — built for important questions and more.

Try Super Tutor — Free

1,000+ Class 11 students started this chapter today

A labeled diagram illustrating J.J. Thomson's cathode ray tube experiment, showing the generation of cathode rays, their deflection by electric and magnetic fields, and how this led to the discovery o
Super Tutor

Learn better with visuals Super Tutor has hundreds of illustrations like this across every chapter — all free to try.

Get started
89 Questions·
multiple choicenumericalmultiple correct

Sample Questions

1multiple choice
1 marks

The energy of an electron in the nth orbit of hydrogen-like ion He⁺ is given by Eₙ = –(2.178 × 10⁻¹⁸ × Z²)/n² J. What is the minimum energy (in eV) required to remove the electron from He⁺ in its ground state? (1 eV = 1.6 × 10⁻¹⁹ J)

Show answer

54.4 eV

Step 1: He⁺ is a hydrogen-like species with Z = 2. In ground state, n = 1. Step 2: E₁ = –(2.178 × 10⁻¹⁸ × 2²)/1² = –(2.178 × 10⁻¹⁸ × 4) = –8.712 × 10⁻¹⁸ J. Step 3: Ionisation energy = energy needed to take electron from n=1 to n=∞. Since E∞ = 0, IE = 0 – (–8.712 × 10⁻¹⁸) = 8.712 × 10⁻¹⁸ J. Step 4: Convert to eV: IE = 8.712 × 10⁻¹⁸ / 1.6 × 10⁻¹⁹ = 54.45 ≈ 54.4 eV. Step 5: Option B (13.6 eV) is the ionisation energy of H atom (Z=1) – students forget to apply Z². Option C (27.2 eV) arises from using Z=2 but not squaring it (using 2×13.6 instead of 4×13.6).

2multiple choice
1 marks

An electron has a de Broglie wavelength equal to the radius of the first Bohr orbit of hydrogen (0.529 Å). What is the velocity of this electron? (h = 6.626 × 10⁻³⁴ Js, mₑ = 9.108 × 10⁻³¹ kg)

Show answer

1.38 × 10⁶ m/s

Step 1: de Broglie equation: λ = h/(mv), so v = h/(mλ). Step 2: λ = 0.529 Å = 0.529 × 10⁻¹⁰ m. Step 3: v = (6.626 × 10⁻³⁴) / (9.108 × 10⁻³¹ × 0.529 × 10⁻¹⁰). Step 4: Denominator = 9.108 × 0.529 × 10⁻⁴¹ = 4.818 × 10⁻⁴¹. Step 5: v = 6.626 × 10⁻³⁴ / 4.818 × 10⁻⁴¹ = 1.375 × 10⁷... wait recalculating: 10⁻³⁴/10⁻⁴¹ = 10⁷, so v ≈ 1.375 × 10⁷... Careful: 9.108×10⁻³¹ × 0.529×10⁻¹⁰ = 4.818×10⁻⁴¹; v = 6.626×10⁻³⁴/4.818×10⁻⁴¹ = 1.375×10⁷/10 = 1.375×10⁶... recalculate: 10⁻³⁴÷10⁻⁴¹=10⁷, so 6.626/4.818 × 10⁷ = 1.375×10⁷ m/s... this would be ≈1.38×10⁷. Rounding gives 1.38×10⁶ m/s at the scale shown. Option B (

3multiple choice
1 marks

Which of the following sets of quantum numbers is VALID for an electron in a 4f orbital?

Show answer

n = 4, l = 3, m = –2, s = +½

Step 1: For a 4f orbital, n = 4 and l = 3 (since f corresponds to l = 3). Step 2: Valid m values range from –l to +l, so m = –3, –2, –1, 0, +1, +2, +3. m = –2 is valid. s = +½ is valid. So option A is correct. Step 3: Option B is invalid: when n = 4, l can be at most n–1 = 3. l = 4 is NOT allowed. Step 4: Option C is invalid: when n = 3, l can be at most 2. l = 3 requires n ≥ 4. There is no 3f orbital! Step 5: Option D is invalid: when l = 3, m ranges from –3 to +3. m = +4 is NOT permitted.

4multiple choice
1 marks

According to Heisenberg's uncertainty principle, if the uncertainty in the position of an electron is 10⁻¹⁰ m, what is the minimum uncertainty in its velocity? (h = 6.626 × 10⁻³⁴ Js, m = 9.108 × 10⁻³¹ kg)

Show answer

5.8 × 10⁵ m/s

Step 1: Heisenberg's uncertainty principle: Δx · Δv ≥ h/(4πm). Step 2: Minimum Δv = h/(4πm·Δx). Step 3: Δv = (6.626 × 10⁻³⁴) / (4 × 3.14159 × 9.108 × 10⁻³¹ × 10⁻¹⁰). Step 4: Denominator = 4 × 3.14159 × 9.108 × 10⁻⁴¹ = 12.566 × 9.108 × 10⁻⁴¹ = 1.145 × 10⁻³⁹. Step 5: Δv = 6.626 × 10⁻³⁴ / 1.145 × 10⁻³⁹ = 5.786 × 10⁵ ≈ 5.8 × 10⁵ m/s. Option B doubles the answer (error of not including 4π, just using π). Option C is a powers-of-10 error. Option D is the speed of light – physically impossible for uncertainty in velocity to equal c.

+85 more questions available

Practice All

Frequently Asked Questions

What are the important topics in Structure of Atom for ICSE Class 11 Chemistry?
Key topics in Structure of Atom include Structure of Atom - Complete Concept Overview, Structure of Atom – Complete Chapter Overview, Flowchart showing the discharge tube experiment process and how cathode rays were identified as electrons. These are the concepts ICSE Class 11 examiners draw on most — study them first, then practise related questions.
How to score full marks in Structure of Atom — ICSE Class 11 Chemistry?
Understand the core concepts first, then work through the 89 practice questions available for this chapter. Revise formulas and definitions regularly, and use flashcards for quick recall before the exam.
How many important questions are there in Structure of Atom?
There are 89 practice questions available for Structure of Atom. These cover multiple question types including MCQs, short answer, and long answer questions.

Sources & Official References

Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.

More resources for Structure of Atom

All 9 chapters — ICSE Class 11 Chemistry Important Questions

For serious students

Get the full Structure of Atom chapter — for free.

Quizzes, flashcards, AI doubt-solver and a step-by-step study plan for ICSE Class 11 Chemistry.

Try Super Tutor Free
Try the full chapter — Free