Name: Unit 2: Atomic Structure Additional Practice Period: 1. Which particles have approximately the same mass? an electron and an alpha particle an electron and a proton a neutron and an alpha particle a neutron and a proton 2. Which particle has no charge? electron neutron ammonia ethanol positron proton 3. Which substance can not be broken down by a chemical change? electrons, only neutrons, only protons and electrons protons and neutrons propanal zirconium 4. Which particles are found in the nucleus of an atom? 5. Which subatomic particles have a mass of approximately 1 atomic mass unit each? proton and electron proton and neutron neutron and positron electron and positron 6. An atom of lithium-7 has an equal number of electrons and neutrons electrons and protons positrons and neutrons positrons and protons 7. A student constructs a model for comparing the masses of subatomic particles. The student selects a small, metal sphere with a mass of gram to represent an electron. A sphere with which mass would be most appropriate to represent a proton? g g an electron and a neutron an electron and a proton a proton and a neutron a proton and a positron g g 8. Which two particles have opposite charges? 9. What is the approximate mass of a proton? 1 u 0.0005 u electron and neutron electron and positron proton and electron proton and neutron 1 g 0.0005 g 10. Which two particles each have a mass approximately equal to one atomic mass unit? 11. Which electron configuration represents the electrons in an atom of Ga in an excited state? 2-8-17-3 2-8-17-4 2-8-18-3 2-8-18-4 12. An atom contains 22 neutrons and 40 nucleons. What is the total number of protons in the atom? 18 22 40 62
13. The notation for the nuclide 137 55Cs gives information about mass number, only atomic number, only both mass number and atomic number neither mass number nor atomic number 14. A neutral atom contains 12 neutrons and 11 electrons. The number of protons in this atom is 1 11 12 23 15. What can be determined if only the atomic number of an atom is known? the total number of neutrons in the atom, only the total number of protons in the atom, only the total number of protons and the total number of neutrons in the atom the total number of protons and the total number of electrons in the atom 16. What is the total number of electrons in an atom of an element with an atomic number of 18 and a mass number of 40? 18 22 40 58 17. Which quantity represents the number of protons in an atom? atomic number oxidation number number of neutrons number of valence electrons 19. Every chlorine atom has 7 electrons 17 neutrons a mass number of 35 an atomic number of 17 20. What is the charge of the nucleus of an oxygen atom? 0 2 +8 +16 21. An atomic mass unit is defined as exactly 22. Which particle has the least mass? alpha particle beta particle neutron proton 23. The mass of a proton is approximately equal to the mass of an alpha particle an electron a neutron a positron 24. The mass of a proton is approximately equal to the total mass of 1,836 electrons neutrons helium nuclei alpha particles 18. Which statement about one atom of an element identifies the element? The atom has 1 proton. The atom has 2 neutrons. The sum of the number of protons and neutrons in the atom is 3. The difference between the number of neutrons and protons in the atom is 1. 25. The atomic mass of magnesium is the weighted average of the atomic masses of all of the artificially produced isotopes of Mg all of the naturally occurring isotopes of Mg the two most abundant artificially produced isotopes of Mg the two most abundant naturally occurring isotopes of Mg
26. In which list are the elements arranged in order of increasing atomic mass? Cl, K, Ar Fe, Co, Ni Te, I, Xe Ne, F, Na 32. An atom that has 13 protons and 15 neutrons is an isotope of the element nickel silicon aluminum phosphorus 27. Which quantity can vary among atoms of the same element? mass number atomic number number of protons numbers of electrons 28. Which particle has a mass that is approximately the same as the mass of a proton? an alpha particle a beta particle a neutron a positron 29. The number of neutrons in the nucleus of an atom can be determined by adding the atomic number to the mass number subtracting the atomic number from the mass number adding the mass number to the atomic mass subtracting the mass number from the atomic number 30. Which two particles make up most of the mass of a hydrogen-2 atom? electron and neutron electron and proton proton and neutron proton and positron 33. All isotopes of a given element must have the same atomic mass atomic number mass number number of neutrons 34. Compared to an atom of calcium-40, an atom of potassium-39 contains fewer protons neutrons occupied sublevels occupied principal energy levels 35. Which notations represent different isotopes of the element sodium? 36. In which pair of elements do the nuclei of the atoms contain the same number of neutrons? 37. What is the total number of neutrons in an atom of O-18? 18 16 10 8 31. Which subatomic particle is found in the nucleus of all isotopes of hydrogen? proton neutron electron positron 38. Which isotopic notation represents an atom of carbon-14? 6 8C 8 6C 6 14C 14 6C
39. In which pair does each atom have the same number of neutrons? 24 Mg and 24 Na 15 N and 16 O 32 Si and 31 P 32 S and 33 S 40. The atomic mass of titanium is 47.88 atomic mass units. This atomic mass represents the total mass of all the protons and neutrons in an atom of Ti total mass of all the protons, neutrons, and electrons in an atom of Ti weighted average mass of the most abundant isotope of Ti weighted average mass of all the naturally occurring isotopes of Ti 41. The atomic masses and the natural abundances of the two naturally occurring isotopes of lithium are shown in the table below. 42. What information is necessary to determine the atomic mass of the element chlorine? the atomic mass of each artificially produced isotope of chlorine, only the relative abundance of each naturally occurring isotope of chlorine, only the atomic mass and the relative abundance of each naturally occurring isotope of chlorine the atomic mass and the relative abundance of each naturally occurring and artificially produced isotope of chlorine 43. Which statement best explains why most atomic masses on the Periodic Table are decimal numbers? Atomic masses are determined relative to an H 1 standard. Atomic masses are determined relative to an O 16 standard. Atomic masses are a weighted average of the naturally occurring isotopes. Atomic masses are an estimated average of the artificially produced isotopes. Which numerical setup can be used to determine the atomic mass of lithium? (0.075)(6.02 u) + (0.925)(7.02 u) (0.925)(6.02 u) + (0.075)(7.02 u) (7.5)(6.02 u) + (92.5)(7.02 u) (92.5)(6.02 u) + (7.5)(7.02 u) 44. 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
Base your answers to questions 45 through 47 on the information below The element boron, a trace element in Earth's crust, is found in foods produced from plants. Boron has only two naturally occurring stable isotopes, boron-10 and boron-11. 45. State, in terms of subatomic particles, one difference between the nucleus of a carbon-11 atom and the nucleus of a boron-11 atom. 46. Write an isotopic notation of the heavier isotope of the element boron. Your response must include the atomic number, the mass number, and the symbol of this isotope. 47. Compare the abundance of the two naturally occurring isotopes of boron. Base your answers to questions 48 through 50 on the information below. The bright-line spectra for three elements and a mixture of elements are shown below. 48. State the total number of valence electrons in a cadmium atom in the ground state. 49. Identify all the elements in the mixture. 50. Explain, in terms of both electrons and energy, how the bright-line spectrum of an element is produced.
Base your answers to questions 51 and 52 on the information below An atom in an excited state has an electron configuration of 2-7-2. 51. Write the electron configuration of this atom in the ground state. 52. Explain, in terms of subatomic particles, why this excited atom is electrically neutral.