Class 9th Science Chapter 4 Structure of the Atom
| Textbook | NCERT |
| Class | 9th |
| Subject | Science |
| Chapter | 4th |
| Chapter Name | Structure of the Atom |
| Category | Class 9th Science |
| Medium | English |
| Source | Last Doubt |
| Class 9th Science Chapter – 4 Structure of the Atom MCQ with answer What is structure of atom Class 9, What is the structure of atoms, What are the 5 parts of an atom, What is atom full answer, What is atom Class 9 Topper, What are atoms made of, What are the 4 types of structures in chemistry, Who discovered the structure of atom, How big is atom, Who discovered atom First Class 9, What is the smallest unit of matter. |
Class 9th Science Chapter 4 Structure of the Atom
Chapter – 4
Structure of Atom
Question Answer
| (1) Which isotope is used in the nuclear power plants to generate electricity? A. Uranium 235 B. Iodine 131 C. Cobalt 60 D. Uranium 238 Answer – (A) Uranium 235 |
| (2) What was the source of alpha particles in Rutherford scattering experiment? A. Hydrogen nucleus B. Argon nucleus C. Helium nucleus D. None of these Answer – (C) Helium nucleus |
| (3) Which of the following does not match the characteristics of an Isotope? A. Isotopes of some elements are radioactive B. Isotopes are the atoms of different elements C. Isotopes differ in number of neutrons D. Isotopes have similar chemical properties Answer – (B) Isotopes are the atoms of different elements |
| (4) Who discovered the electron? A. Rutherford B. Chadwick C. Thomson D. Goldstein Answer –(C) Thomson |
| (5) The nucleons are? A. Protons and electrons B. Neutrons and electrons C. Protons and neutrons D. None of these Answer – (C) Protons and neutrons |
| (6) Why was the Thomson’s Model of an atom failed? i. It could not explain the screening of negative charges from that of positive ii. It did not tell about the presence of electrons iii. It did not give an idea about the discrete energy levels iv. It explained the atom as a whole to be electrically neutral. Choose the correct option from the following: A. Only (iii) B. Both (i) & (iii) C. Only (i) D. Both (ii) & (iv) Answer – (B) Both (i) & (iii) |
| (8) Which scientist gave the concept of fixed energy levels around the nucleus? A. Ernest Rutherford B. Neils Bohar C. J.J.Thomsan D. None of these Answer – (B) Neils Bohar |
| (9) Which of the following elements does not exhibit the electrovalencey? A. Sodium B. Calcium C. Carbon D. Chlorine Answer – (C) Carbon |
| (10) Which of the following statements is incorrect about the structure of an atom? i. The whole mass of an atom is concentrated in the nucleus ii. The atom is an indivisible particle iii. The atom as a whole is neutral iv. All the atoms are stable in their basic state Choose the right option among the following: A. (i) and (iii) B. Only (ii) C. (ii) and (iv) D. None of these Answer – (C) (ii) and (iv) |
| (11) What property of an element determines its chemical behaviour? A. Size of an element B. Valency of an element C. Molar mass of the element D. None of these Answer – (B) Valency of an element |
| (12) What prevents an atom from being collapsed? A. The nuclear forces B. Movement of electrons in discrete energy levels C. The electron-electron repulsions D. All of these Answer – (B) Movement of electrons in discrete energy levels |
| (13) Which radioactive element is used in the treatment of cancer? A. Iodine-131 B. Uranium-234 C. Plutonium-239 D. Cobalt-60 Answer – (D) Cobalt-60 |
| (14) The atomic number of sodium is 11 and its mass number is 23. It has? A. 11 neutrons and 12 protons B. 12 protons and 11 electrons C. 11 electrons and 12 neutrons D. 12 electrons and 11 neutrons Answer – (C) 11 electrons and 12 neutrons |
| (15) Which of the following is an incorrect statement in reference with observation in Rutherford’s α-particle scattering experiment? A. Some of the α-particles rebound after hitting the gold foil B. Some of the particles deflected from their path C. Some of the particles not pass through the gold foil D. Most of the particles pass straight through the gold foil Answer – (A) Some of the α-particles rebound after hitting the gold foil |
| (16) Which of the following pairs are isobars? A. 17Cl35 & 17Cl37 B. 18Ar40 & 20Ca40 C. 6C12 & 6C14 D. None of these Answer – (B) 18Ar40 & 20Ca40 |
| (17) Why do most of the elements try to participate in the chemical combinations? i. To gain more electrons ii. To achieve Inert Gas configuration iii. To complete their octet iv. To complete their inner shells Choose the correct option among the following A. Both (i) & (iii) B. Both (ii) & (iii) C. Only (ii) D. Both (i) & (iv) Answer – (B) Both (ii) & (iii) |
| (18) The isotope deuterium of hydrogen has? A. No neutrons and one proton B. One neutrons and two protons C. One electron and two neutron D. One proton and one neutro Answer –(D) One proton and one neutron |
| (19) The electrons present in the outermost shell are called A. Valency electrons B. Octate electrons C. Duplet electrons D. Valence electrons Answer – (D) Valence electrons |
| (20) An alpha particle contains? A. 4 positive charge and 2 mass unit B. 2 positive charge and 4 mass unit C. 2 positive charge and 2 mass unit D. 4 positive charge and 4 mass unit Answer – (B) 2 positive charge and 4 mass unit |
| (21) The isotope used to remove the brain tumours and treatment of cancer is? A. U-235 B. Na-24 C. Iodine D. C0-60 Answer – (D) C0-60 |
| (22) The electronic configuration of chlorine is? A. 2,7 B. 2,8,8,7 C. 2,8,7 D. 2,7,8 Answer – (C) 2,8,7 |
| (23) In an alpha scattering experiment, few alpha particles rebounded because? A. Most of the space in the atom is occupied B. Positive charge of the atoms very little space C. The mass of the atom is concentrated in the centre D. All the positive charge and mass of the atom is concentrated in small volume Answer – (B) Positive charge of the atoms very little space |
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