This quiz works best with JavaScript enabled. Home > Cbse > Class 9 > Science > Structure Of The Atom > Class 9 Science Chapter 4 Structure Of The Atom – Quiz 1 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 9 Science Chapter 4 Structure Of The Atom Quiz 1 (60 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. What is the electronic configuration of Magnesium? A) 2, 8, 2. B) 2, 3. C) 2, 8, 3. D) 2, 8, 1. Show Answer Correct Answer: A) 2, 8, 2. 2. What is the major drawback of Rutherford's atomic model? A) Electrons revolve around the nucleus in well-defined orbits. B) Electrons lose their energy and fall into the nucleus. C) Atom is highly unstable. D) All of the above. Show Answer Correct Answer: B) Electrons lose their energy and fall into the nucleus. 3. How many electrons can the first energy level of an atom fit? A) Eight. B) Four. C) Six. D) Two. Show Answer Correct Answer: D) Two. 4. True or false:Atoms make up everything around you. A) True. B) False. C) All the above. D) None of the above. Show Answer Correct Answer: A) True. 5. Chlorine has a atomic number of 17. This means it will have: A) 7 valence electrons and a valency of 1. B) 1 valence electrons and a valency of 7. C) All the above. D) None of the above. Show Answer Correct Answer: A) 7 valence electrons and a valency of 1. 6. Which of the following is NOT the correct explanation of Thompson's atomic model? A) The atom is positively charged sphere. B) Electrons are embedded in the positive sphere. C) The positive and negative charges balance each other. D) Protons and neutrons are embedded in the center of the sphere. Show Answer Correct Answer: D) Protons and neutrons are embedded in the center of the sphere. 7. Which scientist determined that almost all of an atom's mass of is located in its nucleus? A) Rutherford. B) Thomson. C) Democritus. D) Dalton. Show Answer Correct Answer: A) Rutherford. 8. Thomson's Model of an atom is similar to A) Seeds in the Mango. B) Seeds In the Apple. C) Seeds in the Watermelon. D) None of the above. Show Answer Correct Answer: C) Seeds in the Watermelon. 9. The mass number of an atom is the A) Number of protons in its nucleus. B) Combined total of protons and neutrons in its nucleus. C) All the above. D) None of the above. Show Answer Correct Answer: B) Combined total of protons and neutrons in its nucleus. 10. How many d orbitals are there in a given sublevel? A) 7. B) 5. C) 1. D) 3. Show Answer Correct Answer: B) 5. 11. What are isotopes? A) Atoms of different elements with the same atomic number. B) Atoms of the same element with different atomic numbers. C) Atoms of the same element with the same atomic number but different mass numbers. D) Atoms of different elements with different atomic numbers and mass numbers. Show Answer Correct Answer: C) Atoms of the same element with the same atomic number but different mass numbers. 12. Which best summarizes the subatomic particles and their electrical charge? A) Proton= PositiveNeutron= No chargeElectron=Negative. B) Proton= No chargeNeutron= NegativeElectron=Positive. C) Proton= PositiveNeutron= NegativeElectron= No charge. D) Proton = NegativeNeutron= PositiveElectron= No charge. Show Answer Correct Answer: A) Proton= PositiveNeutron= No chargeElectron=Negative. 13. Which subatomic particle determines the identity of an atom? A) Proton. B) Neutron. C) Electron. D) None of the above. Show Answer Correct Answer: A) Proton. 14. A spontaneous process in which unstable nuclei lose energy by emitting radiation A) Radioactivity. B) Alpha radiation. C) Radioactive decay. D) Radiation. Show Answer Correct Answer: C) Radioactive decay. 15. Which of the following statements is incorrect about the structure of an atom?i. The whole mass of an atom is concentrated in the nucleusii. The atom is an indivisible particleiii. The atom as a whole is neutraliv. All the atoms are stable in their basic stateChoose the right option among the following: A) (i) and (iii). B) Only (ii). C) (ii) and (iv). D) None of these. Show Answer Correct Answer: C) (ii) and (iv). 16. What is the maximum number of electrons that an orbital can have? A) 3 electrons. B) 1 electron. C) 2 electrons. D) 4 electrons. Show Answer Correct Answer: C) 2 electrons. 17. Which substance undergoes sublimation process when heated? Which material undergoes the process of heating when heated? A) Sodium chloride / Natrium klorida. B) Iodine / iodin. C) Lead (II) Bromide / Plumbum (II) Bromide. D) Chlorine / Klorin. Show Answer Correct Answer: B) Iodine / iodin. 18. Which of the following statements is true about the kinetic theory of matter? A) The particles in liquids are packed closely together in an orderly manner. B) The particles in solids move randomly. C) The forces between the particles of gases are stronger than those of liquids. D) The energy content of a gas is higher than that of a solid. Show Answer Correct Answer: D) The energy content of a gas is higher than that of a solid. 19. The net charge on an atom is A) Positive. B) Neutral. C) Negative. D) None of the these. Show Answer Correct Answer: B) Neutral. 20. An element has the mass number 12 and atomic number 6. The number of neutrons in it is: A) 6. B) 8. C) 10. D) 4. Show Answer Correct Answer: A) 6. 21. What atom matches this electron configuration?[Xe] 6s$^{2 }$4f$^{14 }$5d$^{9}$ A) Mercury. B) Gold. C) Platinum. D) Thallium. Show Answer Correct Answer: B) Gold. 22. The nucleus of an atom makes up ..... of its mass. A) Almost none. B) 50%. C) 90%. D) 99.9%. Show Answer Correct Answer: D) 99.9%. 23. Which subatomic particle was discovered first? A) Proton. B) Electron. C) Neutron. D) None of the above. Show Answer Correct Answer: A) Proton. 24. Rutherford's alpha scattering experiment led to the discovery of A) Nucleus. B) Proton. C) Electron. D) Neutron. Show Answer Correct Answer: A) Nucleus. 25. The process in which some substances spontaneously emit radiation A) Radioactive decay. B) Radioactivity. C) Beta radiation. D) Radiation. Show Answer Correct Answer: B) Radioactivity. 26. Radiation emitted by a certain radioisotope is used to kill bacteria and other microorganisms in foods such as potatoes. What is the isotope? A) Iodine-131. B) Cobalt-60. C) Phosphorus-32. D) Carbon-14. Show Answer Correct Answer: B) Cobalt-60. 27. If the number of electrons in an atom changes you make a(n) ..... A) Isotope. B) Ion. C) Isomer. D) New element. Show Answer Correct Answer: B) Ion. 28. What is the subtopic of atomic structure? A) Study of plant cells. B) Arrangement of subatomic particles. C) Behavior of sound waves. D) Classification of chemical elements. Show Answer Correct Answer: B) Arrangement of subatomic particles. 29. The first model of an atom was given by A) J.J. Thomson. B) N. Bohr. C) Rutherford. D) E. Goldstein. Show Answer Correct Answer: A) J.J. Thomson. 30. WhIch sub atomic particle vary between isotopes of an element? A) Protons, electrons, and atomic mass. B) Protons, electrons, and atomic number. C) Neutrons and electrons. D) Neutrons only. Show Answer Correct Answer: D) Neutrons only. 31. Which atomic model proposed the presence of electrons inside a positive sphere? A) Rutherford's Atomic Model. B) Bohr's Atomic Model. C) Quantum Mechanical Model. D) Thomson's Atomic Model. Show Answer Correct Answer: D) Thomson's Atomic Model. 32. What are valence electrons? A) Electrons in the first orbital always. B) The number of electrons present in the outermost orbital. C) Nucleus. D) The outermost shell. Show Answer Correct Answer: B) The number of electrons present in the outermost orbital. 33. Isotopes have different number of? A) Protons. B) Electrons. C) Neutrons. D) Protons and Neutrons. Show Answer Correct Answer: C) Neutrons. 34. Electrons where introduced by A) J J Thomson. B) Ernest Rutherford. C) Neil Bohr. D) None of the above. Show Answer Correct Answer: A) J J Thomson. 35. Who stated that atoms cannot be divided? A) Bohr. B) Rutherford. C) Thomson. D) Dalton. Show Answer Correct Answer: D) Dalton. 36. The sum of the protons and neutrons in a nucleus is ..... A) The element number the element number. B) Avogadro's number. C) The atomic number. D) The mass number. Show Answer Correct Answer: D) The mass number. 37. The rays and particles-alpha and beta particles and gamma rays-that are emitted by radioactive materials A) Radioactive decay. B) Radiation. C) Radioactivity. D) Cathode ray. Show Answer Correct Answer: B) Radiation. 38. According to Aufbau principle, which orbital fills after the 4s orbital? A) Zd. B) 4p. C) 4f. D) 5s. Show Answer Correct Answer: A) Zd. 39. Of the atom's mass is found where? A) Neutrons. B) Protons. C) Electron cloud. D) Nucleus. Show Answer Correct Answer: D) Nucleus. 40. A particle with two protons and two neutrons, with a 2+ charge; is equivalent to a helium-4 nucleus, can be represented by $\alpha$; and is emitted during radioactive decay A) Alpha particle. B) Alpha radiation. C) Gamma ray. D) Beta particle. Show Answer Correct Answer: A) Alpha particle. 41. An electron has this charge A) Positive. B) Negative. C) Neutral. D) None of the above. Show Answer Correct Answer: B) Negative. 42. What atom matches this electron configuration?1s$^{2}$2s$^{2}$2p$^{6}$3s$_{}$$^{2}$ A) Aluminum. B) Neon. C) Magnesium. D) Potassium. Show Answer Correct Answer: C) Magnesium. 43. What is an atom made up of? A) Protons and neutrons. B) Protons and electrons. C) Neutrons and electrons. D) Protons, neutrons, and electrons. Show Answer Correct Answer: D) Protons, neutrons, and electrons. 44. Helium atom has an atomic mass of 4u and two protons in its nucleus. How many neutrons does it have? A) 2. B) 3. C) 0. D) 4. Show Answer Correct Answer: A) 2. 45. What is the symbol of manganese? A) Mg. B) M. C) Mn. D) Ma. Show Answer Correct Answer: C) Mn. 46. What is the mass number of an atom which contains 28 protons, 28 electrons, and 34 neutrons? A) 28. B) 62. C) 90. D) 56. Show Answer Correct Answer: B) 62. 47. Isotopes of the same element have ..... A) The same number of neutrons but different numbers of protons. B) The same number of neutrons but different numbers of electrons. C) The same number of protons but different numbers of electrons. D) The same number of protons but different numbers of neutrons. Show Answer Correct Answer: D) The same number of protons but different numbers of neutrons. 48. What quantities vary between isotopes of an element? A) Protons, electrons, and atomic mass. B) Protons, electrons, and atomic number. C) Neutrons and electrons. D) Neutrons and atomic mass. Show Answer Correct Answer: D) Neutrons and atomic mass. 49. Three isotopes of oxygen occur in nature:oxygen-16, oxygen-17, and oxygen-18. If the atomic mass of oxygen is 15.9994, which of the three isotopes, if any, is the most abundant? A) Oxygen-16. B) Oxygen-17. C) Oxygen-18. D) All are equally abundant. Show Answer Correct Answer: A) Oxygen-16. 50. Where are Protons located in an atom? A) Outside. B) Around. C) Electron cloud. D) Nucleus. Show Answer Correct Answer: D) Nucleus. 51. What is the relationship between the size of the nucleus and the size of the atom? A) The nucleus is about half the size of the atom. B) The nucleus is twice as big as the atom. C) The nucleus is about 100 times smaller than the atom. D) The nucleus is about 100, 000 times smaller than the atom. Show Answer Correct Answer: D) The nucleus is about 100, 000 times smaller than the atom. 52. What is the atomic number of an atom? A) The total number of protons and neutrons in the nucleus. B) The total number of protons in the nucleus. C) The total number of electrons in the atom. D) The total number of subatomic particles in the atom. Show Answer Correct Answer: B) The total number of protons in the nucleus. 53. What assumption did Neil Bohr make in his atomic model? A) Only certain special orbits of electrons are allowed inside the atom. B) Electrons do not radiate energy while revolving in discrete orbits. C) Energy is emitted or absorbed by an atom only when an electron moves from one orbit to another. D) All of the above. Show Answer Correct Answer: D) All of the above. 54. A subatomic particle in an atom's nucleus that has a positive charge of 1+ A) Nucleus. B) Electron. C) Proton. D) Neutron. Show Answer Correct Answer: C) Proton. 55. Atoms of different elements with different atomic number but some mass number are called as Isobars.True Or False A) True. B) False. C) None of the above. D) None of the above. Show Answer Correct Answer: A) True. 56. Atoms consists of protons, neutrons, and ..... A) Electrons. B) Neutrons. C) Protons. D) +1. E) -1. Show Answer Correct Answer: A) Electrons. 57. What is at the center of every atom? A) A molecule. B) An electron. C) A nucleus. D) A compound. Show Answer Correct Answer: C) A nucleus. 58. How many protons, electrons and neutrons does an neutral atom of Calcium have? Its atomic number is 20 and the mass number is 40. A) 20 protons, 18 electrons and 40 neutrons. B) 20 protons, 20 electrons and 20 neutrons. C) 40 protons, 40 electrons and 20 neutrons. D) 20 protons, 18 electrons and 20 neutrons. Show Answer Correct Answer: B) 20 protons, 20 electrons and 20 neutrons. 59. The center of an atom that holds protons and neutrons? A) Electron. B) Nucleus. C) Model. D) Neutron. Show Answer Correct Answer: B) Nucleus. 60. What is the approximate radius of a nucleus? A) 1x10$^{-13}$ m. B) 1x10$^{-11}$ m. C) 1x10$^{-14}$ m. D) 1x10$^{-12}$ m. Show Answer Correct Answer: C) 1x10$^{-14}$ m. 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