Chapter 3: Atoms and Molecules Assertion-Reason Questions | science Class 9 CBSE

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Chapter 3: Atoms and Molecules Assertion-Reason Questions | science Class 9 CBSE | ByteNotes.in

Assertion-Reason

Check the statement and reason

A-R

Question 1

Logic Check

Assertion (A): Dalton proposed that atoms are indivisible. Reason (R): Atoms cannot be created or destroyed during chemical reactions.

Reasoning Options

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Assertion-Reason

Check the statement and reason

A-R

Question 2

Logic Check

Assertion (A): Law of conservation of mass states that mass is neither created nor destroyed. Reason (R): During a chemical reaction, the total mass of reactants equals the total mass of products.

Reasoning Options

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Assertion-Reason

Check the statement and reason

A-R

Question 3

Logic Check

Assertion (A): Water always has hydrogen and oxygen in a mass ratio of 1:8. Reason (R): The law of constant proportion states that a chemical compound always contains the same elements in a fixed ratio by mass.

Reasoning Options

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Assertion-Reason

Check the statement and reason

A-R

Question 4

Logic Check

Assertion (A): Dalton's atomic theory helped explain the law of definite proportions. Reason (R): Atoms combine in fixed ratios to form compounds.

Reasoning Options

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Assertion-Reason

Check the statement and reason

A-R

Question 5

Logic Check

Assertion (A): Atomic symbols are always written with capital letters only. Reason (R): IUPAC has made it mandatory to use two capital letters for all elements.

Reasoning Options

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Assertion-Reason

Check the statement and reason

A-R

Question 6

Logic Check

Assertion (A): The relative atomic mass of hydrogen is 1 u. Reason (R): Hydrogen is the lightest element and consists of one proton.

Reasoning Options

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Assertion-Reason

Check the statement and reason

A-R

Question 7

Logic Check

Assertion (A): A molecule of water is made up of two hydrogen atoms and one oxygen atom. Reason (R): The atomicity of water is three.

Reasoning Options

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Assertion-Reason

Check the statement and reason

A-R

Question 8

Logic Check

Assertion (A): Atoms of noble gases exist as monoatomic molecules. Reason (R): Noble gases are inert and do not form chemical bonds easily.

Reasoning Options

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Assertion-Reason

Check the statement and reason

A-R

Question 9

Logic Check

Assertion (A): Ozone is a triatomic molecule of oxygen. Reason (R): It contains three atoms of oxygen chemically bonded together.

Reasoning Options

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Assertion-Reason

Check the statement and reason

A-R

Question 10

Logic Check

Assertion (A): Polyatomic ions carry more than one charge. Reason (R): Polyatomic ions are made up of multiple atoms bonded with excess or deficit electrons.

Reasoning Options

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Chapter sections

Chapter 3: Atoms and Molecules | Assertion-Reason

Assertion (A): Dalton proposed that atoms are indivisible. Reason (R): Atoms cannot be created or destroyed during chemical reactions.

Assertion (A): Law of conservation of mass states that mass is neither created nor destroyed. Reason (R): During a chemical reaction, the total mass of reactants equals the total mass of products.

Assertion (A): Water always has hydrogen and oxygen in a mass ratio of 1:8. Reason (R): The law of constant proportion states that a chemical compound always contains the same elements in a fixed ratio by mass.

Assertion (A): Dalton's atomic theory helped explain the law of definite proportions. Reason (R): Atoms combine in fixed ratios to form compounds.

Assertion (A): Atomic symbols are always written with capital letters only. Reason (R): IUPAC has made it mandatory to use two capital letters for all elements.

Assertion (A): The relative atomic mass of hydrogen is 1 u. Reason (R): Hydrogen is the lightest element and consists of one proton.

Assertion (A): A molecule of water is made up of two hydrogen atoms and one oxygen atom. Reason (R): The atomicity of water is three.

Assertion (A): Atoms of noble gases exist as monoatomic molecules. Reason (R): Noble gases are inert and do not form chemical bonds easily.

Assertion (A): Ozone is a triatomic molecule of oxygen. Reason (R): It contains three atoms of oxygen chemically bonded together.

Assertion (A): Polyatomic ions carry more than one charge. Reason (R): Polyatomic ions are made up of multiple atoms bonded with excess or deficit electrons.

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