MCQ questions for class 9 Science Chapter 3 Atoms and Molecules
Question 1: Who proposed the idea of the existence of atoms?
Democritus
Dalton
Thomson
Rutherford
Question 2: What is the charge of a proton?
Positive
Negative
Neutral
No charge
Question 3: The atomic number of an element is determined by the number of:
Protons
Neutrons
Electrons
Nucleons
Question 4: What is the mass number of an atom?
Number of protons
Number of electrons
Sum of protons and neutrons
Number of neutrons
Question 5: Who discovered the electron?
Democritus
Dalton
Thomson
Rutherford
Question 6: What is the smallest particle of an element that retains its chemical properties?
Molecule
Atom
Ion
Neutron
Question 7: In a neutral atom, the number of electrons is equal to the number of:
Protons
Neutrons
Positrons
Nucleons
Question 8: The sum of protons and neutrons in the nucleus of an atom is called:
Atomic number
Mass number
Atomic mass
Isotopic mass
Question 9: Which of the following is a diatomic molecule?
O2
H2O
CO2
CH4
Question 10: What is the chemical symbol for sodium?
S
So
Na
Sa
Question 11: How many atoms are present in one molecule of water (H2O)?
1
2
3
4
Question 12: What is the chemical formula for methane?
CH4
CO2
H2O
O2
Question 13: The process of the combination of two or more atoms to form a molecule is called:
Ionization
Dissociation
Combination
Decomposition
Question 14: What is the charge of a neutron?
Positive
Negative
Neutral
No charge
Question 15: Which subatomic particle is responsible for the chemical properties of an element?
Proton
Electron
Neutron
Nucleus
Question 16: What is the formula for the compound sulfur hexafluoride?
SF4
SF6
SO2
SO3
Question 17: Who proposed the planetary model of the atom?
Democritus
Dalton
Thomson
Rutherford
Question 18: What is the chemical symbol for gold?
Au
Ag
Fe
Cu
Question 19: How many electrons are there in the outermost shell of a chlorine atom?
1
2
7
8
Question 20: Which of the following is a cation?
Cl-
Na+
F-
O2-
Welcome to our platform, your one-stop for MCQ questions for Class 9 Science. This page is designed to assist you in reinforcing key scientific concepts and getting ready for your exams with our Class 9 Science MCQs.
Whether you're revisiting old topics or exploring new ones, our Science MCQs for Class 9 cover all areas of your syllabus. Practice these multiple-choice questions to test your knowledge and understanding of the subject, boosting your confidence in the process.
Remember, you can always find us Class 9 Science multiple choice questions, Online MCQ practice for Class 9 Science, or Comprehensive MCQ questions for Class 9 Science. Start your journey towards becoming a Class 9 Science whiz today