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