Atoms and Molecules Quiz - CBSE Class 9 Science

Free practice quiz: Atoms and Molecules (CBSE Class 9 Science). 16 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This CBSE Class 9 Science practice quiz has 16 multiple-choice questions on Atoms and Molecules, and 16 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. What is an atom?

   1. A pure substance made of two or more elements
   2. The smallest unit of matter
   3. A type of molecule
   4. A chemical reaction
   Show answer

   Answer: B. The smallest unit of matter

   An atom is the smallest unit of matter that retains the properties of an element.

2. Which of the following correctly represents a compound?

   1. NaCl
   2. He
   3. O2
   4. N
   Show answer

   Answer: A. NaCl

   NaCl (sodium chloride) is a compound formed from the combination of sodium and chlorine atoms.

3. Which of the following statements is true about atoms and elements?

   1. All atoms are identical
   2. An element consists of only one type of atom
   3. Atoms can be created or destroyed in a chemical reaction
   4. Elements can exist as molecules
   Show answer

   Answer: B. An element consists of only one type of atom

   An element is defined as a pure substance that cannot be broken down into simpler substances and consists of only one type of atom.

4. Which law states that mass is neither created nor destroyed in a chemical reaction?

   1. Law of Conservation of Mass
   2. Law of Definite Proportions
   3. Law of Multiple Proportions
   4. Law of Chemical Equilibrium
   Show answer

   Answer: A. Law of Conservation of Mass

   The Law of Conservation of Mass states that the total mass of reactants is equal to the total mass of products in a chemical reaction.

5. Which of the following describes how chemical formulas represent compounds?

   1. They show the number of protons
   2. They indicate the ratio of different elements
   3. They represent only the physical state
   4. They show the mass of elements
   Show answer

   Answer: B. They indicate the ratio of different elements

   Chemical formulas represent compounds by indicating the types and ratio of atoms (elements) that make up the compound.

More questions in this quiz

Answers and explanations are in the full quiz.

1. What particles are found in the nucleus of an atom?
2. What determines the atomic number of an element?
3. What is the mass number of an atom?
4. What do we call a positively charged ion?
5. How many atoms are found in a mole?
6. What is the primary difference between an atom and a molecule?
7. What is the formula for finding the number of moles in a substance?
8. What is an ionic bond?
9. What determines the chemical properties of an element?
10. What is the difference between a homogeneous mixture and a compound?
11. What is Avogadro's number used for?

More quizzes

• Matter and its Properties▶ Play

Browse all Chemistry quizzes

More to play