Teacher: Mr. gerraputa Print Close Name: 1. Given the electron dot diagram: The valence electrons represented by the electron dot diagram could be those of atoms in Group 1. 13 3. 3 2. 15 4. 16 2. Which statement best describes the nucleus of an aluminum atom? 1. It has a charge of +13 and is surrounded by a total of 10 electrons. 2. It has a charge of +13 and is surrounded by a total of 13 electrons. 3. It has a charge of 13 and is surrounded by a total of 10 electrons. 4. It has a charge of 13 and is surrounded by a total of 13 electrons. 3. Base your answer to the question on the information below. An atom has an atomic number of 9, a mass number of 19, and an electron configuration of 2-6-1. Figure 1 Explain why the number of electrons in the second and third shells shows that this atom is in an excited state. Answer: 4. Which of these phrases best describes an atom? 1. a positive nucleus surrounded by a hard negative shell 2. a positive nucleus surrounded by a cloud of negative charges 3. a hard sphere with positive particles uniformly embedded 4. a hard sphere with negative particles uniformly embedded Page 1 of 17
5. Which atoms represent different isotopes of the same element? 1. and 2. and 3. and 4. and 9. The atomic mass of an element is defined as the weighted average mass of that element s 10. 1. most abundant isotope 2. least abundant isotope 3. naturally occuring isotopes 4. radioactive isotopes 6. Which of the following atoms has the greatest nuclear charge? 1. Al 3. Si 2. Ar 4. Na 7. What is a possible mass number of a sodium atom? 1. 1 3. 12 2. 11 4. 23 8. Write an electron configuration for a silicon atom in an excited state. Answer: What is the total number of electrons present in an atom of? 1. 27 3. 39 2. 32 4. 86 11. What is the total number of electrons in a Cu + ion? 1. 28 3. 30 2. 29 4. 36 12. What are the nucleons in an atom? 1. protons and 3. neutrons and electrons electrons 2. protons and neutrons 4. neutrons and positrons Page 2 of 17
13. Which particle contains the greatest number of electrons? 17. Which diagram represents the nucleus of an atom of? 1. Na 3. F 2. Na+ 4. F 1. 3. 14. What is the total number of neutrons in an atom of? 2. 4. 1. 82 3. 207 2. 125 4. 289 15. Which atoms contain the same number of neutrons? 16. 1. and 2. and 3. and 4. and An atom in the ground state contains 8 valence electrons. This atom is classified as a 1. metal 3. noble gas 2. semimetal 4. halogen 18. If 75.0% of the isotopes of an element have a mass of 35.0 amu and 25.0% of the isotopes have a mass of 37.0 amu, what is the atomic mass of the element? 1. 35.0 amu 3. 36.0 amu 2. 35.5 amu 4. 37.0 amu 19. Which ion has the same electron configuration as an H ion? 1. Cl 3. K+ 2. F 4. Li+ Page 3 of 17
20. Base your answer on the data table, which shows three isotopes of neon. In terms of atomic particles, state one difference between these three isotopes of neon. Answer: 21. All samples of an element are composed of atoms with the same 1. atomic mass 3. number of nucleons 2. atomic number 4. number of neutrons 22. Neutral atoms of the same element can differ in their number of 1. neutrons 3. protons 2. positrons 4. electrons Page 4 of 17
23. Two atoms will always have the same atomic number if they have the same 26. What is the mass number of an atom which contains 28 protons, 28 electrons and 34 neutrons? 1. mass number 3. number of neutrons 2. number of protons 4. number of nucleons 1. 28 3. 62 2. 56 4. 90 24. 27. Which term refers to the region of an atom where an electron is most likely to be found? 1. orbital 3. quantum 2. orbit 4. spectrum 25. Which statement best describes an electron? 1. It has a smaller mass than a proton and a negative charge. 2. It has a smaller mass than a proton and a positive charge. 3. It has a greater mass than a proton and a negative charge. 4. It has a greater mass than a proton and a positive charge. In an experiment, alpha particles were used to bombard gold foil. As a result of this experiment, the conclusion was made that the nucleus of an atom is 28. 1. smaller than the atom and positively charged 2. smaller than the atom and negatively charged 3. larger than the atom and positively charged 4. larger than the atom and negatively charged Spectral lines produced from the radiant energy emitted from excited atoms are thought to be due to the movements of electrons 1. from lower to higher energy levels 2. from higher to lower energy levels 3. in their orbitals 4. out of the nucleus Page 5 of 17
29. Compared to the entire atom, the nucleus of the atom is 1. smaller and contains most of the atom s mass 2. smaller and contains little of the atom s mass 3. larger and contains most of the atom s mass 4. larger and contains little of the atom s mass 30. Which particle has a mass of approximately one atomic mass unit and a unit positive charge? 1. a neutron 3. a beta particle 2. a proton 4. an alpha particle 31. The diagram shows the characteristic spectral line patterns of four elements. Also shown are spectral lines produced by an unknown substance. Which pair of elements is present in the unknown? 1. lithium and sodium 3. lithium and helium 2. sodium and hydrogen 4. helium and hydrogen Page 6 of 17
32. The characteristic bright-line spectrum of an element is produced when its electrons 1. form a covalent bond 2. form an ionic bond 3. move to a higher energy state 4. return to a lower energy state 35. Base your answer to the question on the information and the bright-line spectra represented below. Many advertising signs depend on the production of light emissions from gas-filled glass tubes that are subjected to a high-voltage source. When light emissions are passed through a spectroscope, brightline spectra are produced. 33. Which particle has the same electron configuration as a potassium ion? 1. fluoride ion 3. neon atom 2. sodium ion 4. argon atom 34. Which is an electron configuration for an atom of chlorine in the excited state? 1. 2-8-7 3. 2-8-6-1 2. 2-8-8 4. 2-8-7-1 Identify the two gases in the unknown mixture. 1. A and B 3. B and C 2. A and D 4. C and D 36. Which Lewis electron-dot diagram below correctly shows a selenium atom in the ground state? 1. 3. 2. 4. Page 7 of 17
37. Which Lewis electron-dot diagram properly shows a sulfur atom in the ground state? 1. 2. 3. 4. 38. Base your answer to this question on the information below. The accepted values for the atomic mass and percent natural abundance of each naturally occurring isotope of silicon are given in the data table below. Figure 2 What is a correct numerical setup for calculating the atomic mass of Si? 1. (27.98)(92.22) + (28.98)(04.69) + (29.97)(3.09) 2. (27.98)(0.0469) + (28.98)(0.9222) + (29.97)(0.0309) 3. (27.98)( 04.69) + (28.98)(92.22) + (29.97)(0.0309) 4. (27.98)(0.9222) + (28.98)(0.0469) + (29.97)(0.0309) Page 8 of 17
39. Choose the correct Lewis electron-dot diagram for an atom of boron. 1. 2. 3. 4. 40. Given the bright-line spectra of three elements and the spectrum of a mixture formed from at least two of these elements: Which elements are present in this mixture? 1. E and D, only 2. E and G, only 3. D and G, only 4. D, E, and G Page 9 of 17
41. In the late 1800s, experiments using cathode ray tubes led to the discovery of the 1. electron 3. positron 2. neutron 4. proton 42. Base your answer to the question on the information below. In the modern model of the atom, each atom is composed of three major subatomic (or fundamental) particles. Figure 3 State the charge associated with each type of subatomic particle contained in the nucleus of the atom. Answer: Page 10 of 17
43. Base your answer to the question on the information and diagram below. One model of the atom states that atoms are tiny particles composed of a uniform mixture of positive and negative charges. Scientists conducted an experiment where alpha particles were aimed at a thin layer of gold atoms. Most of the alpha particles passed directly through the gold atoms. A few alpha particles were deflected from their straight-line paths. An illustration of the experiment is shown below. Figure 4 A few of the alpha particles were deflected. What does this evidence suggest about the structure of the gold atoms? Answer: Page 11 of 17
44. John Dalton was an English scientist who proposed that atoms were hard, indivisible spheres. In the modern model, the atom has a different internal structure. a Identify one experiment that led scientists to develop the modern model of the atom. b Describe this experiment. c State one conclusion about the internal structure of the atom, based on this experiment. Answer: 45. Which pair must represent atoms of the same element? 46. 1. and 2. and 3. and 4. and Which substance is composed of atoms that all have the same atomic number? 1. magnesium 3. ethane 2. methane 4. ethene 47. What is the maximum number of electrons that may be present in the fourth principal energy level of an atom? 1. 8 3. 18 2. 2 4. 32 Page 12 of 17
48. How many protons are in the nucleus of an atom of beryllium? 51. Which symbols represent atoms that are isotopes of each other? 1. 5 3. 9 2. 2 4. 4 49. 1. 14 C and 14 N 2. 16 O and 18 O 3. 131 I and 131 I 4. 222 Rn and 222 Ra An atom that contains 8 protons, 8 electrons, and 9 neutrons has 1. an atomic number of 9 3. a mass number of 17 2. an atomic number of 4. a mass number of 16 25 50. A substance that is composed only of atoms having the same atomic number is classified as 1. a compound 3. a homogeneous mixture 2. an element 4. a heterogeneous mixture 52. The major portion of an atom s mass consists of 1. electrons and protons 3. neutrons and positrons 2. electrons and 4. neutrons and protons neutrons 53. Which atom contains exactly 15 protons? 1. phosphorus-32 3. oxygen-15 2. sulfur-32 4. nitrogen-15 Page 13 of 17
54. Element X has two isotopes. If 72.0% of the element has an isotopic mass of 84.9 atomic mass units, and 28.0% of the element has an isotopic mass of 87.0 atomic mass units, the average atomic mass of element X is numerically equal to 55. 1. (72.0 + 84.9) (28.0 + 87.0) 2. (72.0-84.9) (28.0 + 87.0) 3. 4. (72.0 84.9) + (28.0 87.0) All the isotopes of a given atom have 56. 1. the same mass number and the same atomic number 2. the same mass number but different atomic numbers 3. different mass numbers but the same atomic number 4. different mass numbers and different atomic numbers As an atom becomes an ion, its mass number 1. decreases 2. increases 3. remains the same 57. Which particles are isotopes of each other? 58. 1. and 2. and 3. and 4. and An atom of carbon-12 and an atom of carbon-14 differ in 1. atomic number 3. nuclear charge 2. mass number 4. number of electrons 59. Which particles are found in the nucleus of an atom? 1. electrons, only 3. protons and electrons 2. neutrons, only 4. protons and neutrons 60. An electron has a charge of 1. 1 and the same mass as a proton 2. +1 and the same mass as a proton 3. 1 and a smaller mass than a proton 4. +1 and a smaller mass than a proton Page 14 of 17
Answer Key for atomic structure 1. 1 21. 2 2. 2 22. 1 41. 1 42. Acceptable responses include, but are not limited to, this example: Protons are positively charged (+) and neutrons have no charge (0). 3. Examples: The third shell has one electron before the second shell is completely filled. The electron configuration is not 2-7, which is the ground state for an atom with atomic number 9. 23. 2 43. Acceptable responses include, but are not limited to, these examples: Alpha particles were deflected by the positively charged nucleus. nucleus - charged 4. 2 24. 1 44. a Acceptable responses include, but are not limited to, these examples: gold foil (Rutherford) cathode rays (Thomson) electron bombardment (Moseley) b Acceptable responses include, but are not limited to, this example: In the gold-foil experiment, gold foil was bombarded with alpha particles. Some alpha particles were deflected. In the cathode ray experiment charged plates deflected electrons. Mosley bombarded different metals with a beam of electrons c Acceptable responses include, but are not limited to, these examples: The gold-foil experiment shows that an atom is mostly empty space. Page 15 of 17
The gold-foil experiment shows that an atom has a small dense core. The gold-foil experiment shows that an atom has a positively charged center. The cathode ray experiment concluded that electrons have a very small mass and a negative charge. The electron bombardment concluded that each atomic nucleus contains a characteristic number of protons that we call an elements atomic number. 5. 3 25. 1 6. 2 26. 3 7. 4 27. 1 8. 28. 2 45. 2 46. 1 47. 4 48. 4 Acceptable responses include, but are not limited to: 2-7-5 1-8-5 2-8-3-1 9. 3 29. 1 10. 1 30. 2 11. 1 31. 4 12. 2 32. 4 13. 1 33. 4 14. 2 34. 3 15. 4 35. 2 16. 3 36. 4 17. 2 37. 3 18. 2 38. 4 49. 3 50. 2 51. 2 52. 4 53. 1 54. 3 55. 3 56. 3 57. 1 58. 2 Page 16 of 17
19. 4 39. 2 20. 40. 1 59. 4 60. 3 Acceptable responses include, but are not limited to, these examples: Each isotope has a different number of neutrons. different number of neutrons Ne-22 has two more neutrons than Ne-20 and one more neutron than Ne-21. Page 17 of 17