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. Which of the following atom has no neutron in its nucleus ? Protium Tritium Lithium Helium None 2. $$_{18} Ar^{40} , \ _{20} Ca^{40}$$ and $$ {_{19}}K^{40}$$ Isotopes Isobars Isomers Isotones None 3. Positively charged radiation was discovered by? Bohr Chadwick Thomson Goldstein None 4. If the atomic number of an atom is 17 and the mass number is 35 then the number of neutrons will be 35 18 17 52 None 5. Which of the following has zero valency? Sodium Krypton Aluminium Beryllium 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. Observations II and III Observation I only None of these observations disprove Thomsons model Observation III only None 7. 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 8. The number that represents, how many times one atom of an element is heavier than mass of one atom of carbon \(_{6}^{12}\textrm{C}\) Relative atomic mass All of these Atomic number Atomic weight None 9. 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: 1.67x 2.67x 0.67x 2x None 10. 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 Very few α-particles getting absorbed Get condensed or concentrated None 11. Which of the following concept was considered in Rutherford's atomic model? The electrical neutrality of atom Existence of nuclear forces of attraction on the electrons. All of the above Electrons revolve around nucleus at a very high speed None 12. 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. true, true, correct explanation false, true true, false false, false None 13. Rutherford's alpha particle scattering experiment established that: protons are not evenly distributed throughout an atom electrons have a negative charge atoms are made of protons, neutrons, and electrons electrons have a positive charge None 14. 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? Alpha particles should have passed through the foil with little or no deflection. All the alpha particles would have been deflected by the foil. Alpha particles should have become embedded in the foil. All the alpha particles should have bounced straight back from the foil. None 15. Which of the following is always a whole number? Atomic radius Atomic number Atomic weight Atomic volume None 16. The fundamental particles present in the nucleus of an atom are: Alpha particle and electrons Neutrons and electrons Electrons, neutrons and protons Neutrons and protons None 17. Which is correct statement about proton? None of these Proton is ionized hydrogen atom. Proton is ionized oxygen molecule. Proton is nucleus of deuterium. None 18. The mass of an atom is concentrated inside the ............. of an atom. neutron nucleus electron proton None 19. 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 (ii) (ii) and (iii) (ii) and (iv) (i) and (iii) None 20. The α−particle scattering experiment of Rutherford concluded that Electrons occupy discrete energy levels The positive charge of the atom is concentrated in a very small space The nucleus is made up of protons and neutrons The number of electrons is exactly equal to number of protons in atom 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.
