Ncert – class 9- science – Chapter 4 – Structure of the Atom 1 Welcome to your Ncert - class 9- science - Chapter 4 – Structure of the Atom 1 1. Positively charged radiation was discovered by? Bohr Goldstein Thomson Chadwick None 2. The number that represents, how many times one atom of an element is heavier than mass of one atom of carbon \(_{6}^{12}\textrm{C}\) All of these Relative atomic mass Atomic weight Atomic number None 3. Rutherford's alpha particle scattering experiment established that: electrons have a positive charge protons are not evenly distributed throughout an atom electrons have a negative charge atoms are made of protons, neutrons, and electrons None 4. Which of the following concept was considered in Rutherford's atomic model? Existence of nuclear forces of attraction on the electrons. Electrons revolve around nucleus at a very high speed All of the above The electrical neutrality of atom None 5. Which is correct statement about proton? Proton is ionized hydrogen atom. None of these Proton is nucleus of deuterium. Proton is ionized oxygen molecule. None 6. Which of the following observations from Rutherfords experiment disprove Thomsons proposal that the atom is a positively charged sphere? table { border-collapse: collapse; width: 100%; } th, td { border: 1px solid #dddddd; text-align: left; padding: 8px; } th { background-color: #f2f2f2; }ObservationDescriptionObservation IMost of the fast-moving α-particles passed straight through the gold foil.Observation IISome of the α-particles were deflected by the foil by small angles.Observation IIIOne out of every 12000 particles appeared to rebound. Observation I only Observations II and III None of these observations disprove Thomsons model Observation III only None 7. Which of the following are isotopes?(i) Atom, whose nucleus contains 20p+15n(ii) Atom whose nucleus contains 20p+17n(iii) Atom, whose nucleus contains 18p+22n(iv) Atom, whose nucleus contains 18p+21n (i) and (iii) (ii) and (iv) (i) and (ii) (ii) and (iii) None 8. The fundamental particles present in the nucleus of an atom are: Neutrons and electrons Alpha particle and electrons Electrons, neutrons and protons Neutrons and protons None 9. Which of the following has zero valency? Krypton Beryllium Sodium Aluminium None 10. $$_{18} Ar^{40} , \ _{20} Ca^{40}$$ and $$ {_{19}}K^{40}$$ Isotones Isobars Isomers Isotopes None 11. Which of the following is always a whole number? Atomic volume Atomic radius Atomic number Atomic weight None 12. The α−particle scattering experiment of Rutherford concluded that The nucleus is made up of protons and neutrons The positive charge of the atom is concentrated in a very small space The number of electrons is exactly equal to number of protons in atom Electrons occupy discrete energy levels None 13. In a particular set-up, the Rutherford alpha ray scattering experiment using thin gold foil, N(θ) is found to be x. If a platinum foil of double thickness is used instead, N(θ) would be: 2.67x 0.67x 1.67x 2x None 14. If the atomic number of an atom is 17 and the mass number is 35 then the number of neutrons will be 35 52 17 18 None 15. In Rutherford's experiment, a thin gold foil was bombarded with alpha particles. If 'Thomson's Plum-Pudding' model of the atom was applicable, then what should have happened? All the alpha particles would have been deflected by the foil. All the alpha particles should have bounced straight back from the foil. Alpha particles should have become embedded in the foil. Alpha particles should have passed through the foil with little or no deflection. None 16. Which of the following atom has no neutron in its nucleus ? Lithium Protium Helium Tritium None 17. If Rutherford would have used β-particles instead of α-particles in his Goldleaf experiment which of the following observation would definitely not have been made? Majority of β-particles passing unperfected through the foil Wave nature of electron Get condensed or concentrated Very few α-particles getting absorbed None 18. Statement I :\(^{12}\textrm{C}\) C is an isotope of \(^{14}\textrm{C}\)Statement II: The nuclei of both atoms have the same number of neutrons. false, false true, true, correct explanation true, false false, true None 19. The mass of an atom is concentrated inside the ............. of an atom. neutron nucleus electron proton None 20. An atom as a whole is electrically neutral because the number of protons is equal to the number of electrons. Is the given statement true? Depends on the type of atom No Cannot be determined Yes None Time's up Please Share This Share this content Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Opens in a new window Leave a Reply Cancel replyCommentEnter your name or username to commentEnter your email address to commentEnter your website URL (optional) Save my name, email, and website in this browser for the next time I comment.
