Are these practice questions for Journey Inside the Atom based on the CBSE pattern?

Yes. Every practice question is modeled on the CBSE Class 9 Science exam pattern — including MCQs, assertion-reason questions, and short-answer formats that frequently appear in CBSE papers.

Are the practice questions for Journey Inside the Atom free?

Yes. Every chapter includes free practice questions for Class 9 students to get you started.

What types of questions are included?

The practice set for Journey Inside the Atom mainly includes MCQs and CBSE-style short-answer questions, with instant feedback on each answer. For full-length textbook practice, use the NCERT Solutions page.

Are the practice questions suitable for board exam preparation?

Yes. The questions test the same concepts and depth that CBSE asks in board exams. After finishing, also solve the NCERT and NCERT Exemplar exercises for Journey Inside the Atom for full coverage.

How many practice questions are there for Journey Inside the Atom?

The number scales with chapter length and concept density. Each chapter typically has 15-50 practice questions across MCQ and short-answer formats.

Journey Inside the Atom Class 9 Science Practice Questions with Answers

easy

Evaluate the 'watermelon' analogy for Thomson's model and justify whether it is a fitting comparison.

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easy

Name the scientist who discovered the neutron.

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easy

Define the term 'atomic number' of an element and state the symbol used to represent it.

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easy

An atom has an atomic number of 17 and a mass number of 35. Calculate the number of protons, neutrons, and electrons in this neutral atom.

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easy

A particle has a mass nearly equal to that of a proton but carries no electrical charge. Apply your knowledge of subatomic particles to identify it and state its location within an atom.

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easy

An atom has an electronic configuration of 2, 8, 5. Apply the octet rule to determine its valency.

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easy

What are valence electrons?

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easy

Solve for the mass number of an atom that contains 15 protons and 16 neutrons.

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easy

Define the term 'isotopes' and give an example.

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easy

An atom has the electronic configuration 2, 8, 8. Propose its likely chemical nature and justify your proposal based on the concept of valency.

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easy

Name the three fundamental subatomic particles of an atom and list their respective relative charges.

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easy

Create a single, concise rule to justify whether two given atoms are isotopes of each other, based on their subatomic particles.

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medium

Create a word problem for a fellow student that requires them to justify the identity and valency of an element 'Q' based on its subatomic particles. The element Q has 13 protons and 14 neutrons.

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medium

Examine the statement: 'Isotopes of an element have identical chemical properties but different physical properties.' Justify this statement by contrasting the isotopes of carbon,

{ }_{6}^{12} \text{C}

and

{ }_{6}^{14} \text{C}

.

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medium

An atom of sodium is represented as

{ }_{11}^{23} \text{Na}

. If it loses one electron, it forms a sodium ion (

Na^{+}

). Analyze the change in the number of protons, neutrons, and electrons, and calculate the resulting charge on the ion.

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medium

Analyze the results of the gold foil experiment. Explain how two key observations led Rutherford to reject Thomson's model and propose his nuclear model of the atom.

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medium

Demonstrate the distribution of electrons in the K, L, and M shells for a magnesium atom (

{ }_{12} \text{Mg}

) according to the Bohr-Bury rules, and state its valency.

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medium

Compare and contrast the concepts of atomic number (Z) and mass number (A). Apply this knowledge to solve for the complete composition (protons, neutrons, and electrons) of a neutral atom of Uranium,

{ }_{92}^{235} \text{U}

.

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medium

List the three main conclusions that Ernest Rutherford drew from his alpha-particle scattering experiment.

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medium

Justify why isotopes of an element (e.g.,

{}^{12}\text{C}

and

{}^{14}\text{C}

) have nearly identical chemical properties, whereas isobars (e.g.,

{}^{40}\text{Ar}

and

{}^{40}\text{Ca}

) have distinctly different chemical properties.

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medium

An element has 13 protons and 14 neutrons. Apply the standard notation (

{ }_{Z}^{A} \text{X}

) to represent this atom.

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medium

Compare Rutherford's atomic model with J.J. Thomson's model. Analyze two key differences in how they describe the distribution of charge and mass within an atom.

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medium

Define 'mass number'. An atom of an element contains 13 protons and 14 neutrons. Identify its atomic number and its mass number.

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medium

You have discovered a new element named 'Novium'. Propose a two-letter symbol for it and justify your choice based on IUPAC conventions. Also, formulate a reason why a symbol like 'nV' would be incorrect.

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medium

Critique Rutherford's planetary model of the atom. Justify why it was a significant advancement over Thomson's model, but ultimately failed to explain atomic stability, a problem that Bohr's model later addressed.

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medium

Explain the concept of valency. Determine the valency of sodium (Atomic number Z = 11) and chlorine (Atomic number Z = 17) by first writing their electronic configurations.

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medium

Critique Bohr's model of the atom. While it successfully explained atomic stability and line spectra for hydrogen, justify why it is considered an incomplete model in modern atomic theory.

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medium

An atom has an atomic number of 11 and a mass number of 23. Identify the number of protons, neutrons, and electrons in this atom.

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medium

Describe J.J. Thomson's model of the atom. Explain why this model is often compared to a 'plum pudding' or a watermelon.

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medium

The element Boron exists as two isotopes:

{}_{5}^{10}\text{B}

(19.9% abundance) and

{}_{5}^{11}\text{B}

(80.1% abundance). Justify why the atomic mass listed on the periodic table is a decimal value (

10.81 \text{ u}

) by calculating the average atomic mass.

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medium

Formulate a detailed explanation comparing the chemical reactivity of Potassium (

Z=19

) and Argon (

Z=18

). Justify your comparison by creating their electronic configurations and evaluating their valencies and tendencies to achieve a stable octet.

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medium

Calculate the average atomic mass of Boron, which exists as two isotopes:

{ }_{5}^{10} \text{B}

with a natural abundance of 19.9% and

{ }_{5}^{11} \text{B}

with a natural abundance of 80.1%.

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medium

Analyze why Bohr's model of the atom was considered a significant improvement over Rutherford's model, specifically in addressing the problem of atomic stability.

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medium

Evaluate the statement: 'The discovery of the neutron was less significant than the discovery of the electron because it is electrically neutral.' Justify your position by explaining the neutron's crucial roles in atomic structure.

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medium

Describe the Bohr-Bury rule for the maximum number of electrons in a shell. Using this rule, calculate the maximum number of electrons that can be accommodated in the K, L, and M shells.

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hard

Explain the difference between isotopes and isobars, providing one example for each concept. Identify the relationship between two atomic species X and Y, where X has 17 protons and 18 neutrons, and Y has 17 protons and 20 neutrons.

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hard

Summarize the rules approved by IUPAC for writing the chemical symbols of elements. Provide one example for each rule.

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hard

Two atomic species are represented as

{ }_{20}^{40} \text{Ca}

and

{ }_{18}^{40} \text{Ar}

. Examine their composition (protons, neutrons, electrons) and analyze the relationship between them. Contrast their chemical properties based on their electronic configurations.

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hard

Propose how the results of Rutherford's gold foil experiment would have differed if atoms consisted of a heavy, negatively charged nucleus with positively charged electrons orbiting it. Justify your predictions.

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hard

Formulate a hypothesis about the existence of elements in the universe if the strong nuclear force, which binds protons and neutrons, were significantly weaker. Justify your hypothesis by considering the balance of forces within the nucleus.

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hard

Design a hypothetical experiment to prove that a sample of Chlorine contains two isotopes,

{}_{17}^{35}\text{Cl}

and

{}_{17}^{37}\text{Cl}

. Justify your choice of apparatus and predict the results you would observe that would confirm the existence of these two isotopes.

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hard

Evaluate the consequences if electrons were 200 times heavier than they are, but all other properties (charge, etc.) remained the same. Justify how this change would affect: (a) the mass number of a Carbon atom (

{}^{12}\text{C}

), (b) the overall atomic mass of a Carbon atom, and (c) the chemical reactivity of Carbon.

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hard

An element 'X' has an atomic number of 16. (a) Calculate the number of electrons in its valence shell. (b) Analyze whether it will gain or lose electrons to become stable and determine its valency. (c) If this element has 16 neutrons, calculate its mass number. (d) Contrast its reactivity with that of an element with atomic number 18.

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hard

The element Bromine (Br) is found in nature as a mixture of two isotopes:

{ }_{35}^{79} \mathrm{Br}

(49.7% abundance) and

{ }_{35}^{81} \mathrm{Br}

(50.3% abundance). Recall the formula and calculate the average atomic mass of a bromine atom.

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hard

Explain the main postulates of Niels Bohr's model of the atom. Summarize how his model addressed the instability problem of Rutherford's model.

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Journey Inside the AtomClass 9 Science Practice Questions