Review - Atomic Structure

Name: Tuesday, June 03, 2008 Review - Atomic Structure 1. The number of neutrons in the nucleus of an atom can be determined by 1. adding the atomic number to the mass number 3. adding the mass number to the atomic mass 2. subtracting the atomic number from the mass number 4. subtracting the mass number from the atomic number 2. Which two nuclides are isotopes of the same element? 1. and 2. and 3. and 4. and 3. Which electron configuration represents an atom of chlorine in an excited state? 1. 2-8-7 3. 2-8-6-1 2. 2-8-8 4. 2-8-7-1 4. According to the wave-mechanical model of the atom, electrons in an atom 1. travel in defined circles 3. have a positive charge 2. are most likely found in an excited state 4. are located in orbitals outside the nucleus

5. As the number of neutrons in the nucleus of a given atom of an element increases, the atomic number of that element 1. decreases 2. increases 3. remains the same 6. Which conclusion is based on the "gold foil experiment" and the resulting model of the atom? 1. An atom is mainly empty space, and the nucleus has 3. An atom has hardly any empty space, and the nucleus a positive charge. has a positive charge. 2. An atom is mainly empty space, and the nucleus has 4. An atom has hardly any empty space, and the nucleus a negative charge. has a negative charge. 7. 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, bright-line spectra are produced. Identify the two gases in the unknown mixture. 1. A and B 3. B and C 2. A and D 4. C and D

8. An atom of carbon-14 contains 1. 8 protons, 6 neutrons and 6 electrons 3. 6 protons, 8 neutrons and 8 electrons 2. 6 protons, 6 neutrons and 8 electrons 4. 6 protons, 8 neutrons and 6 electrons 9. Naturally occurring boron is composed of two isotopes. The percent abundance and the mass of each isotope are listed below. 19.9% of the boron atoms have a mass of 10.013 atomic mass units. 80.1% of the boron atoms have a mass of 11.009 atomic mass units. Calculate the atomic mass of boron. Figure 1 Answer: atomic mass units 10. What is the total number of neutrons in the nucleus of a neutral atom that has 19 electrons and a mass number of 39? 1. 19 3. 39 2. 20 4. 58 11. Atoms of different isotopes of the same element differ in their total number of 1. electrons 3. protons 2. neutrons 4. valence electrons 12. As an electron in an atom moves from the ground state to the excited state, the electron 1. gains energy as it moves to a higher energy level 3. loses energy as it moves to a higher energy level 2. gains energy as it moves to a lower energy level 4. loses energy as it moves to a lower energy level

13. 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 14. [Refer to figure 1 in question 9] Which expression can be used to calculate the atomic mass of boron? 1. (10.013)(19.9%) + (11.009)(80.1%) 2. 3. (10.013)(19.9%)(11.009)(80.1%) 4. (10.013)(80.1%) + (11.009)(19.9%) 15. Which two atoms are isotopes? 1. and 2. and 3. and 4. and 16. What is the total number of electrons found in an atom of sulfur? 1. 6 3. 16 2. 8 4. 32

17. An atom of an element has 28 innermost electrons and 7 outermost electrons. In which period of the Periodic Table is this element located? 1. 5 3. 3 2. 2 4. 4 18. Which pair must represent atoms of the same element? 1. and 2. and 3. and 4. and 19. Base your answer to the question on the information. Naturally occurring elemental carbon is a mixture of isotopes. The percent composition of the two most abundant isotopes is listed below. 98.93% of the carbon atoms have a mass of 12.00 atomic mass units. 1.07% of the carbon atoms have a mass of 13.00 atomic mass units. Figure 2 Which of the following is a correct numerical setup for calculating the average atomic mass of carbon? 1. 2. 3. 4.

20. The diagram represents an atom of magnesium-26 in the ground state. An atom of Mg-26 in the ground state has valence electrons. 21. What is the total number of neutrons in an atom of? 1. 7 3. 3 2. 10 4. 4 22. Two isotopes of potassium are K-37 and K-42. How many valence electrons are in an atom of K-42 in the ground state? Answer: valence electron(s) 23. What is the total number of neutrons in an atom of an element that has a mass number of 19 and an atomic number of 9? 1. 9 3. 19 2. 10 4. 28

24. 35 37 Neutral atoms of Cl and Cl differ with respect to their number of 1. electrons 3. neutrons 2. protons 4. positrons 25. Which change occurs when a barium atom loses two electrons? 1. It becomes a negative ion and its radius decreases. 3. It becomes a positive ion and its radius decreases. 2. It becomes a negative ion and its radius increases. 4. It becomes a positive ion and its radius increases. 26. The region that is the most probable location of an electron in an atom is 1. the nucleus 3. the excited state 2. an orbital 4. an ion 27. + Potassium ions are essential to human health. The movement of dissolved potassium ions, K (aq), in and out of a nerve cell allows that cell to transmit an electrical impulse. What is the total number of electrons in a potassium ion? electrons 28. What is the total number of neutrons in an atom of? 1. 82 3. 207 2. 125 4. 289

29. Figure 3 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 30. Given the electron dot diagram: The valence electrons represented by the electron dot diagram could be those of atoms in Group 1. 13 (IIIA) 3. 3 (IIIB) 2. 15 (VA) 4. 16 (VIA)

31. Base your answer to this question on the information below. Elements with atomic numbers 112 and 114 have been produced and their IUPAC names are pending approval. However, an element that would be put between these two elements on the Periodic Table has not yet been produced. If produced, this element will be identified by the symbol Uut until an IUPAC name is approved. Figure 4 Which Lewis electron-dot diagram is correct for an atom of Uut? 1. 3. 2. 4. 32. Compared to an atom of phosphorus-31, an atom of sulfur-32 contains 1. one less neutron 3. one more neutron 2. one less proton 4. one more proton 33. Compared to a sodium atom in the ground state, a sodium atom in the excited state must have 1. a greater number of electrons 3. an electron with greater energy 2. a smaller number of electrons 4. an electron with less energy 34. Which principal energy level change by the electron of a hydrogen atom will cause the greatest amount of energy to be absorbed? 1. n = 2 to n = 4 3. n = 4 to n = 2 2. n = 2 to n = 5 4. n = 5 to n = 2

35. Which statement best explains why most atomic masses on the Periodic Table are decimal numbers? 1. Atomic masses are determined relative to an 3. Atomic masses are a weighted average of the naturally H-1 standard. occurring isotopes. 2. Atomic masses are determined relative to an 4. Atomic masses are an estimated average of the artificially O-16 standard. produced isotopes. 36. 2- Which Lewis electron-dot diagram is correct for a S ion? 1. 3. 2. 4. 37. In a sample of pure copper, all atoms have atomic numbers which are 1. the same and the atoms have the same number of 3. different, but the atoms have the same number of electrons electrons 2. the same, but the atoms have a different number of 4. different and the atoms have a different number of electrons electrons 38. 2+ What is the total number of electrons in a Mg ion? 1. 10 3. 14 2. 12 4. 24 39. An electron in an atom moves from the ground state to an excited state when the energy of the electron 1. decreases 2. increases 3. remains the same

40. Which atoms represent different isotopes of the same element? 1. and 2. and 3. and 4. and 41. In a calcium atom in the ground state, the electrons that possess the least amount of energy are located in the 1. first electron shell 3. third electron shell 2. second electron shell 4. fourth electron shell 42. Which diagram represents the nucleus of an atom of? 1. 3. 2. 4. 43. Which electron transition represents a gain of energy? 1. from 2nd to 3rd shell 3. from 3rd to 2nd shell 2. from 2nd to 1st shell 4. from 3rd to 1st shell

44. What is the percent composition by mass of aluminum in Al (SO ) (gram-formula mass = 342 grams/mole)? 2 4 3 1. 7.89% 3. 20.8% 2. 15.8% 4. 36.0% 45. What is the symbol for an atom containing 20 protons and 22 neutrons? 1. 2. 3. 4. 46. The total mass of the protons in an atom of gold-198 is approximately 1. 79 atomic mass units 3. 198 atomic mass units 2. 119 atomic mass units 4. 277 atomic mass units 47. Which statement best describes electrons? 1. They are positive subatomic particles and are found in 3. They are negative subatomic particles and are found the nucleus. in the nucleus. 2. They are positive subatomic particles and are found 4. They are negative subatomic particles and are found surrounding the nucleus. surrounding the nucleus. 48. Which particles are found in the nucleus of an atom? 1. electrons, only 3. protons and electrons 2. neutrons, only 4. protons and neutrons

49. A 100.00-gram sample of naturally occurring boron contains 19.78 grams of boron-10 (atomic mass = 10.01 atomic mass units) and 80.22 grams of boron-11 (atomic mass = 11.01 atomic mass units). Which numerical setup can be used to determine the atomic mass of naturally occurring boron? 1. (0.1978)(10.01) + (0.8022)(11.01) 2. (0.8022)(10.01) + (0.1978)(11.01) 3. 4. 50. Which isotopic notation identifies a metalloid that is matched with the corresponding number of protons in each of its atoms? 24 75 1. Mg and 12 protons 3. As and 75 protons 28 80 2. Si and 14 protons 4. Br and 80 protons

Answer Key for Review - Atomic Structure 1. 2 2. 3 3. 3 4. 4 5. 3 6. 1 7. 2 8. 4 9. 10.8 10. 2 11. 2 12. 1 13. 4 14. 1 15. 2 16. 3 17. 4 18. 2 19. 1 20. 2 21. 4 22. 1 23. 2 24. 3 25. 3 26. 2 27. 18 28. 2 29. 4 30. 1 31. 1 32. 4 33. 3 34. 2 35. 3 36. 4 37. 1 38. 1 39. 2 40. 3 41. 1 42. 2 43. 1 44. 2 45. 1 46. 1

47. 4 48. 4 49. 1 50. 2 Review - Atomic Structure