Chapter 3: Atoms and Molecules
Learning Notes (Set 1) for Class 9 Science
Exam oriented Study Guide for CBSE Class 9 Science
Here are 10 quick question-and-answer notes to help you revise the key concepts from the chapter on Atoms and Molecules. Use these for a quick study session before your exam!
Question 1: Who named the indivisible particles of matter 'atoms'?
Answer: The ancient Greek philosopher Democritus.
Question 2: What did Indian philosopher Maharishi Kanad call the smallest particles of matter?
Answer: He named them 'Parmanu'.
SOURCE: WWW.QUIZNEST.INQuestion 3: Which scientist laid the foundation of chemical sciences by establishing the laws of chemical combination?
Answer: Antoine L. Lavoisier.
You are on Chapter 3: Atoms and Molecules (Learning Notes for Class 9 Science) Set 1
Question 4: What does the Law of Conservation of Mass state?
Answer: Mass can neither be created nor destroyed in a chemical reaction.
Question 5: What is the Law of Constant Proportions?
Answer: In a pure chemical substance, elements are always present in definite proportions by mass.
Question 6: According to Dalton's atomic theory, what are the ultimate particles of matter?
Answer: Atoms.
SOURCE: WWW.QUIZNEST.INQuestion 7: What is an atomic mass unit (amu)?
Answer: A unit used to measure the mass of a single atom.
Question 8: How do atoms of most elements exist?
Answer: They exist as molecules or ions.
You are on Chapter 3: Atoms and Molecules (Learning Notes for Class 9 Science) Set 1
Question 9: Define a molecule.
Answer: A molecule is a group of two or more atoms that are chemically bonded together.
Question 10: What are polyatomic ions?
Answer: A group of atoms carrying a charge.
SOURCE: WWW.QUIZNEST.IN
