# MCQ Questions for Class 9 Science Chapter 3 Atoms and Molecules

Students are advised to practice the NCERT MCQ Questions for Class 9 Science Chapter 3 Atoms and Molecules with Answers Pdf free download is available here. MCQ Questions for Class 9 Science with Answers are prepared as per the Latest Exam Pattern. Students can solve these Atoms and Molecules Class 9 MCQs Questions with Answers and assess their preparation level.

## Atoms and Molecules Class 9 MCQs Questions with Answers

Solving the Atoms and Molecules Multiple Choice Questions of Class 9 Science Chapter 3 MCQ can be of extreme help as you will be aware of all the concepts. These MCQ Questions on Atoms and Molecules Class 9 with answers pave for a quick revision of the Chapter thereby helping you to enhance subject knowledge. Have a glance at the MCQ of Chapter 3 Science Class 9 and cross-check your answers during preparation.

Multiple Choice Questions

Question 1.
Who coined the term ‘Parmanu’ for the smallest indivisible particles?
(a) Leucippus
(b) L. Lavoisier
(d) None of them

Question 2.
The radius of a hydrogen atom is:
(a) 10-2
(b) 10-4
(c) 10-9
(d) 10-10

Question 3.
The most remarkable concept that Dalton’s atomic theory proposed was that of the:
(a) atomic weight
(b) atomic mass
(c) molar mass
(d) none of them

Question 4.
The atomic mass of carbon is:
(a) 12
(b) 14
(c) 16
(d) 23

Question 5.
Compounds composed of metals and non-metals contain:
(a) non-charged species
(b) charged species
(c) both of them
(d) none of them

Question 6.
The formula of ammonium sulphate is:
(a) NHSO4
(b) NH4SO2
(c) NHSO3
(d) (NH4)2SO4

Question 7.
The word “mole” was introduced around 1896 by:
(a) Wilhelm Ostwald
(b) John Dalton
(d) Vergilious

Question 8.
The chemical symbol for sodium is:
(a) So
(b) Sd
(c) NA
(d) Na

Question 9.
Which of the following has a maximum number of atoms?
(a) 18 g of H2O
(b) 18 g of O2
(c) 18 g of CO2
(d) 18 g of CH4

Answer: (d) 18 g of CH4

Question 10.
Which of the following contains a maximum number of molecules?
(a) 1g CO2
(b) 1g N2
(c) 1g H2
(d) 1g CH4

Fill in the Blanks.

Question 11.
In a compound such as water, the ratio of the mass of hydrogen to the mass of oxygen is always ______

Question 12.
Atomic radius is measured in ________

Question 13.
The symbol of iron is Fe from its Latin name _________

Question 14.
One atomic mass unit is a mass unit equal to exactly ________ the mass of one atom of carbon-12.

Answer: $$\frac{1}{12}$$th

Question 15.
The formula unit mass of a substance is a sum of the atomic ______ of all its constituent atoms.

Question 16.
Avogadro number is represented by ________

Question 17.
The relative mass of atoms of all elements is obtained by comparing them with the mass of a _______ atom.

Question 18.
The Avogadro constant 6.022 × 1023 is defined as the number of atoms in exactly ______ of carbon-12.

True/False.

Question 19.
An atom is the smallest particle of the element that cannot usually exist independently and retains all its chemical properties.

Question 20.
The Law of conservation of mass states that mass can neither be created nor destroyed in a chemical reaction.

In others words, it is a converter from ‘grams to moles calculator‘ and ‘moles to grams calculator’ by means of the substance molar mass.

Question 21.
The mass of 1 mole of a substance is equal to its relative atomic or molecular mass in grams.

Question 22.
16u oxygen has 16 atoms of oxygen.

Question 23.
The atomic mass of calcium is 40.

Question 24.
Aluminium is diatomic.

Match the Column.

Question 25.

 A B 1. 1 mole of carbon atoms (i) 1 g of H atoms 2. 1 mole of molecules (ii) Molecular mass in gram 3. 1 mole of hydrogen atoms (iii) Relative mass of those particles in gram 4. 1 mole of any particle (atoms, molecules, ions) (iv) 12-gram carbon atoms

 A B 1. 1 mole of carbon atoms (iv) 12-gram carbon atoms 2. 1 mole of molecules (ii) Molecular mass in gram 3. 1 mole of hydrogen atoms (i) 1 g of H atoms 4. 1 mole of any particle (atoms, molecules, ions) (iii) Relative mass of those particles in gram

Question 26.
What is the value of the Avogadro number?

Question 27.
How many atoms of hydrogen are there in 1g of hydrogen?

Question 28.
What name is given to a group of atoms carrying a charge?

Question 29.
What term is given to the mass of one-mole atoms of a substance?

Question 30.
Write the chemical formula of calcium hydroxide.

Question 31.
Write the chemical formula of sulphuric acid?