MCQs For Class 9 Science

Q1. Who discovered the electron?

Q2. What are 'Canal Rays'?

Q3. The discovery of the nucleus of an atom was done by:

Q4. Which experiment led to the discovery of the nucleus?

Q5. Neutrons were discovered by:

Q6. Thomson’s model of the atom is also known as:

Q7. The subatomic particle which has no charge is:

Q8. What is the charge of a proton?

Q9. The mass of an electron is approximately ________ times the mass of a hydrogen atom.

Q10. According to Rutherford’s experiment, most of the space inside the atom is:

Q11. The discrete orbits of electrons are called:

Q12. Who proposed that electrons revolve in discrete orbits without radiating energy?

Q13. The maximum number of electrons that can be accommodated in the K-shell is:

Q14. The formula to find the maximum number of electrons in a shell is:

Q15. The outermost shell of an atom can accommodate a maximum of how many electrons?

Q16. The atomic number of an element is equal to the number of:

Q17. The mass number of an atom is the sum of:

Q18. Atoms of the same element with the same atomic number but different mass numbers are called:

Q19. Atoms of different elements with different atomic numbers but same mass numbers are called:

Q20. What is the valency of Magnesium (Atomic number 12)?

Q21. The electronic configuration of Chlorine (Atomic number 17) is:

Q22. Which isotope is used in the treatment of cancer?

Q23. Which isotope is used in the treatment of goitre?

Q24. An isotope of which element is used as a fuel in nuclear reactors?

Q25. The number of neutrons in an atom of Hydrogen (Protium) is:

Q26. If K and L shells of an atom are full, then what would be the total number of electrons in the atom?

Q27. Valency of Helium atom is:

Q28. The number of electrons in the valence shell of Noble gases (except Helium) is:

Q29. Which of the following is the correct representation of an element X with atomic number Z and mass number A?

Q30. How many neutrons are present in Nitrogen (Atomic mass = 14, Atomic number = 7)?

Q31. The mass of a proton is taken as:

Q32. The orbits or shells are represented by the letters:

Q33. If an atom has 8 protons and 8 electrons, what is its atomic number?

Q34. Isotopes have:

Q35. The fractional atomic mass of Chlorine (35.5 u) is due to its:

Q36. Which subatomic particle is not present in a normal Hydrogen atom?

Q37. Valency of an element is its:

Q38. What is the valency of Carbon?

Q39. An alpha (α) particle is:

Q40. The central part of the atom where nearly all mass is concentrated is:

Q41. Which shell is closest to the nucleus?

Q42. How many electrons are in the M shell of Sodium (Atomic number 11)?

Q43. Calcium and Argon are examples of:

Q44. Who stated that an atom is indivisible?

Q45. The number of valence electrons in O²⁻ ion is:

Q46. Which of the following is used in determining the age of fossils?

Q47. If an atom has 3 protons and 4 neutrons, its mass number will be:

Q48. Protons and neutrons are collectively called:

Q49. Valency of Sodium is:

Q50. Atoms are electrically ________.