This quiz works best with JavaScript enabled. Home > Class 9 > Class 9 Science Chapter 4 Structure Of The Atom – Quiz 3 🏠 Homepage 📘 Download PDF Books 📕 Premium PDF Books Class 9 Science Chapter 4 Structure Of The Atom Quiz 3 (25 MCQs) Quiz Instructions Select an option to see the correct answer instantly. 1. 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. 2. 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. 3. 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. 4. A subatomic particle in an atom's nucleus that has a positive charge of 1+ A) Proton. B) Electron. C) Neutron. D) Nucleus. Show Answer Correct Answer: A) Proton. 5. 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. 6. Atoms consists of protons, neutrons, and ..... A) Protons. B) Neutrons. C) Electrons. D) +1. E) -1. Show Answer Correct Answer: C) Electrons. 7. What is at the center of every atom? A) An electron. B) A compound. C) A molecule. D) A nucleus. Show Answer Correct Answer: D) A nucleus. 8. 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. 9. The center of an atom that holds protons and neutrons? A) Model. B) Electron. C) Nucleus. D) Neutron. Show Answer Correct Answer: C) Nucleus. 10. What is the approximate radius of a nucleus? A) 1x10$^{-11}$ m. B) 1x10$^{-12}$ m. C) 1x10$^{-13}$ m. D) 1x10$^{-14}$ m. Show Answer Correct Answer: D) 1x10$^{-14}$ m. 11. Neutrons are A) Negative. B) Positive. C) Neutral. D) None of the above. Show Answer Correct Answer: C) Neutral. 12. In E. Goldstein' experiment the rays found was known as A) Canal rays. B) X-rays. C) UV rays. D) Sun rays. Show Answer Correct Answer: A) Canal rays. 13. What is the significance of the atomic number in the periodic table? A) It represents the number of protons in the nucleus of an atom. B) It determines the reactivity of the element. C) It represents the number of electrons in the atom. D) It indicates the mass of the atom. Show Answer Correct Answer: A) It represents the number of protons in the nucleus of an atom. 14. What will weigh more when a chemical change is complete? The reactants before the chemical reaction, or the product after the reaction is complete? A) They both will weigh the same. B) The product always weighs more than the reactant. C) The reactant will weigh more than the product. D) They both will loose mass after the reaction. Show Answer Correct Answer: A) They both will weigh the same. 15. An atom of an element with atomic number 48 and massnumber 120 contains ..... A) 48 protons, 48 electrons, and 72 neutrons. B) 72 protons, 48 electrons, and 48 neutrons. C) 120 protons, 48 electrons, and 72 neutrons. D) 72 protons, 72 electrons, and 48 neutrons. Show Answer Correct Answer: A) 48 protons, 48 electrons, and 72 neutrons. 16. Which charge does a proton have? A) Neutral. B) Negative. C) No charge-battery is dead. D) Positive. Show Answer Correct Answer: D) Positive. 17. Who discovered the Sub atomic particle Proton A) J.J Thomson. B) J.chadwick. C) Rutherford. D) E.Goldstein. Show Answer Correct Answer: D) E.Goldstein. 18. Electrons have ..... charge. A) Positive. B) Negative. C) No. D) None of the above. Show Answer Correct Answer: B) Negative. 19. Do Electrons Carry Positive or Negative Charges A) Positive. B) Negative. C) All the above. D) None of the above. Show Answer Correct Answer: B) Negative. 20. Which subatomic particles are much smaller than the others and have a negative charge? A) Proton. B) Electron. C) Neutron. D) None of the above. Show Answer Correct Answer: B) Electron. 21. The number after an element's name, representing the sum of its protons and neutrons A) Mass number. B) Atomic mass. C) Atomic mass unit. D) Atomic number. Show Answer Correct Answer: A) Mass number. 22. Define Valency A) An atom of each element has a definite Combining Capacity. B) The Average Mass of the atoms of an element measured. C) Element that all have the same number of protons but different numbers of neutrons. D) None of the above. Show Answer Correct Answer: A) An atom of each element has a definite Combining Capacity. 23. Which element has 31 protons? A) Gallium. B) Germanium. C) Gadolinium. D) Polonium. Show Answer Correct Answer: A) Gallium. 24. Deuterium and Tritium are A) Isotopes. B) Isobars. C) Isotones. D) None of the above. Show Answer Correct Answer: A) Isotopes. 25. There are ..... types of atomic orbitals. A) 1. B) 2. C) 3. D) 4. Show Answer Correct Answer: D) 4. ← PreviousNext →Related QuizzesClass 9 Science Chapter 4 Structure Of The Atom Quiz 1Class 9 Science Chapter 4 Structure Of The Atom Quiz 2Class 9 Science Chapter 4 Structure Of The Atom Quiz 4Class 9 Science Chapter 4 Structure Of The Atom Quiz 5Class 9 Science Chapter 4 Structure Of The Atom Quiz 6Class 9 Science Chapter 4 Structure Of The Atom Quiz 7Class 9 Science Chapter 4 Structure Of The Atom Quiz 8Class 9 Science Chapter 4 Structure Of The Atom Quiz 9Class 9 Science Chapter 4 Structure Of The Atom Quiz 10Class 9 Science Chapter 4 Structure Of The Atom Quiz 11 🏠 Back to Homepage 📘 Download PDF Books 📕 Premium PDF Books