Match Each Item with the Correct Statement Below s2

Chapter 4

Matching

Match each item with the correct statement below. a. proton d. electron b. nucleus e. neutron c. atom ____ 1. the smallest particle of an element that retains the properties of that element ____ 2. a positively charged subatomic particle ____ 3. a negatively charged subatomic particle ____ 4. a subatomic particle with no charge ____ 5. the central part of an atom, containing protons and neutrons

Match each item with the correct statement below. a. mass number d. atomic mass b. atomic mass unit e. isotope c. atomic number ____ 6. atoms with the same number of protons, but different numbers of neutrons in the nucleus of an atom ____ 7. the total number of protons and neutrons in the nucleus of an atom ____ 8. the number of protons in the nucleus of an element ____ 9. the weighted average of the masses of the isotopes of an element ____ 10. one-twelfth the mass of a carbon atom having six protons and six neutrons

Multiple Choice Identify the letter of the choice that best completes the statement or answers the question.

____ 11. Who was the man who lived from 460B.C.–370B.C. and was among the first to suggest the idea of atoms? a. Atomos c. Democritus b. Dalton d. Thomson ____ 12. Which of the following was NOT among Democritus’s ideas? a. Matter consists of tiny particles called atoms. b. Atoms are indivisible. c. Atoms retain their identity in a chemical reaction. d. Atoms are indestructible. ____ 13. The smallest particle of an element that retains the properties of that element is a(n) ____. a. atom c. proton b. electron d. neutron ____ 14. Dalton's atomic theory included which idea? a. All atoms of all elements are the same size. b. Atoms of different elements always combine in one-to-one ratios. c. Atoms of the same element are always identical. d. Individual atoms can be seen with a microscope. ____ 15. Which of the following is NOT a part of Dalton's atomic theory? a. All elements are composed of atoms. b. Atoms are always in motion. c. Atoms of the same element are identical. d. Atoms that combine do so in simple whole-number ratios. ____ 16. Which of the following was originally a tenet of Dalton's atomic theory, but had to be revised about a century ago? a. Atoms are tiny indivisible particles. b. Atoms of the same element are identical. c. Compounds are made by combining atoms. d. Atoms of different elements can combine with one another in simple whole number ratios. ____ 17. The comparison of the number of atoms in a copper coin the size of a penny with the number of people on Earth is made to illustrate which of the following? a. that atoms are indivisible b. that atoms are very small c. that atoms are very large d. that in a copper penny, there is one atom for every person on Earth ____ 18. The range in size of most atomic radii is approximately ____. a. 2 to 5 cm c. 5 10 m to 2 10 m b. 2 to 5 nm d. 5 10 m to 2 10 m ____ 19. Dalton hypothesized that atoms are indivisible and that all atoms of an element are identical. It is now known that ____. a. all of Dalton's hypotheses are correct b. atoms of an element can have different numbers of protons c. atoms are divisible d. all atoms of an element are not identical but they must all have the same mass ____ 20. Why did J. J. Thomson reason that electrons must be a part of the atoms of all elements? a. Cathode rays are negatively-charged particles. b. Cathode rays can be deflected by magnets. c. An electron is 2000 times lighter than a hydrogen atom. d. Charge-to-mass ratio of electrons was the same, regardless of the gas used. ____ 21. Which of the following is true about subatomic particles? a. Electrons are negatively charged and are the heaviest subatomic particle. b. Protons are positively charged and the lightest subatomic particle. c. Neutrons have no charge and are the lightest subatomic particle. d. The mass of a neutron nearly equals the mass of a proton. ____ 22. Who conducted experiments to determine the quantity of charge carried by an electron? a. Rutherford c. Dalton b. Millikan d. Thomson ____ 23. What is the relative mass of an electron? a. 1/1840 the mass of a hydrogen atom c. 1/1840 the mass of a C-12 atom b. 1/1840 the mass of a neutron + proton d. 1/1840 the mass of an alpha particle ____ 24. Which hypothesis led to the discovery of the proton? a. When a neutral hydrogen atom loses an electron, a positively-charged particle should remain. b. A proton should be 1840 times heavier than an electron. c. Cathode rays should be attracted to a positively-charged plate. d. The nucleus of an atom should contain neutrons. ____ 25. Which of the following is correct concerning subatomic particles? a. The electron was discovered by Goldstein in 1886. b. The neutron was discovered by Chadwick in 1932. c. The proton was discovered by Thomson in 1880. d. Cathode rays were found to be made of protons. ____ 26. All atoms are ____. a. positively charged, with the number of protons exceeding the number of electrons b. negatively charged, with the number of electrons exceeding the number of protons c. neutral, with the number of protons equaling the number of electrons d. neutral, with the number of protons equaling the number of electrons, which is equal to the number of neutrons ____ 27. The particles that are found in the nucleus of an atom are ____. a. neutrons and electrons c. protons and neutrons b. electrons only d. protons and electrons ____ 28. As a consequence of the discovery of the nucleus by Rutherford, which model of the atom is thought to be true? a. Protons, electrons, and neutrons are evenly distributed throughout the volume of the atom. b. The nucleus is made of protons, electrons, and neutrons. c. Electrons are distributed around the nucleus and occupy almost all the volume of the atom. d. The nucleus is made of electrons and protons. ____ 29. The nucleus of an atom is ____. a. the central core and is composed of protons and neutrons b. positively charged and has more protons than neutrons c. negatively charged and has a high density d. negatively charged and has a low density ____ 30. The atomic number of an element is the total number of which particles in the nucleus? a. neutrons c. electrons b. protons d. protons and electrons ____ 31. An element has an atomic number of 76. The number of protons and electrons in a neutral atom of the element are ____. a. 152 protons and 76 electrons c. 38 protons and 38 electrons b. 76 protons and 0 electrons d. 76 protons and 76 electrons ____ 32. The sum of the protons and neutrons in an atom equals the ____. a. atomic number c. atomic mass b. nucleus number d. mass number ____ 33. What does the number 84 in the name krypton-84 represent? a. the atomic number c. the sum of the protons and electrons b. the mass number d. twice the number of protons ____ 34. All atoms of the same element have the same ____. a. number of neutrons c. mass numbers b. number of protons d. mass ____ 35. Isotopes of the same element have different ____. a. numbers of neutrons c. numbers of electrons b. numbers of protons d. atomic numbers ____ 36. Isotopes of the same element have different ____. a. positions on the periodic table c. atomic numbers b. chemical behavior d. mass numbers ____ 37. In which of the following sets is the symbol of the element, the number of protons, and the number of electrons given correctly? a. In, 49 protons, 49 electrons c. Cs, 55 protons, 132.9 electrons b. Zn, 30 protons, 60 electrons d. F, 19 protons, 19 electrons ____ 38. The mass number of an element is equal to ____. a. the total number of electrons in the nucleus b. the total number of protons and neutrons in the nucleus c. less than twice the atomic number d. a constant number for the lighter elements ____ 39. Using the periodic table, determine the number of neutrons in O. a. 4 c. 16 b. 8 d. 24 ____ 40. How many protons, electrons, and neutrons does an atom with atomic number 50 and mass number 125 contain? a. 50 protons, 50 electrons, 75 neutrons c. 120 neutrons, 50 protons, 75 electrons b. 75 electrons, 50 protons, 50 neutrons d. 70 neutrons, 75 protons, 50 electrons ____ 41. Which of the following statements is NOT true? a. Atoms of the same element can have different masses. b. Atoms of isotopes of an element have different numbers of protons. c. The nucleus of an atom has a positive charge. d. Atoms are mostly empty space. ____ 42. If E is the symbol for an element, which two of the following symbols represent isotopes of the same element? 1. E 2. E 3. E 4. E

a. 1 and 2 c. 1 and 4 b. 3 and 4 d. 2 and 3 ____ 43. Select the correct symbol for an atom of tritium. a. n c. H b. H d. H ____ 44. Which of the following sets of symbols represents isotopes of the same element? a. J J J c. M M M b. L L L d. Q Q Q ____ 45. How is the number of neutrons in the nucleus of an atom calculated? a. Add the number of electrons and protons together. b. Subtract the number of electrons from the number of protons. c. Subtract the number of protons from the mass number. d. Add the mass number to the number of electrons. ____ 46. In which of the following is the number of neutrons correctly represented? a. F has 0 neutrons. c. Mg has 24 neutrons. b. As has 108 neutrons. d. U has 146 neutrons. ____ 47. How do the isotopes hydrogen-1 and hydrogen-2 differ? a. Hydrogen-2 has one more electron than hydrogen-1. b. Hydrogen-2 has one neutron; hydrogen-1 has none. c. Hydrogen-2 has two protons; hydrogen-1 has one. d. Hydrogen-2 has one proton; hydrogen-1 has none. ____ 48. Which of the following isotopes has the same number of neutrons as phosphorus-31? a. P c. Si b. S d. Si ____ 49. What unit is used to measure weighted average atomic mass? a. amu c. angstrom b. gram d. nanogram ____ 50. Which of the following equals one atomic mass unit? a. the mass of one electron b. the mass of one helium-4 atom c. the mass of one carbon-12 atom d. one-twelfth the mass of one carbon-12 atom ____ 51. Which of the following statements is NOT true? a. Protons have a positive charge. b. Electrons are negatively charged and have a mass of 1 amu. c. The nucleus of an atom is positively charged. d. Neutrons are located in the nucleus of an atom. ____ 52. Why do chemists use relative masses of atoms compared to a reference isotope rather than the actual masses of the atoms? a. The actual mass of an electron is very large compared to the actual mass of a proton. b. The actual masses of atoms are very small and difficult to work with. c. The number of subatomic particles in atoms of different elements varies. d. The actual masses of protons, electrons, and neutrons are not known. ____ 53. The atomic mass of an element is the ____. a. total number of subatomic particles in its nucleus b. weighted average of the masses of the isotopes of the element c. total mass of the isotopes of the element d. average of the mass number and the atomic number for the element ____ 54. The atomic mass of an element depends upon the ____. a. mass of each electron in that element b. mass of each isotope of that element c. relative abundance of protons in that element d. mass and relative abundance of each isotope of that element ____ 55. Which of the following is necessary to calculate the atomic mass of an element? a. the atomic mass of carbon-12 b. the atomic number of the element c. the relative masses of the element’s protons and neutrons d. the masses of each isotope of the element

Short Answer

56. List the number of protons, neutrons, and electrons in C.

57. Chlorine has two naturally occurring isotopes, Cl-35 and Cl-37. The atomic mass of chlorine is 35.45. Which of these two isotopes of chlorine is more abundant? 58. Consider an element Z that has two naturally occurring isotopes with the following percent abundances: the isotope with a mass number of 19.0 is 55.0% abundant; the isotope with a mass number of 21.0 is 45.0% abundant. What is the average atomic mass for element Z?

59. A fictitious element X is composed of 10.0 percent of the isotope , 20.0 percent of the isotope , and 70.0 percent of the isotope . Estimate the atomic mass of element X. 60. The element chromium has four naturally occurring isotopes. Use the relative abundance of each to calculate the average atomic mass of chromium.

Cr = 4.34%, Cr = 83.79%, Cr = 9.50%, Cr = 2.37%.

Numeric Response

61. What is the relative charge carried by an electron? 62. What is the relative charge of a proton? 63. About how many more times massive is a proton than an electron? 64. Use the periodic table to determine the number of electrons in a neutral atom of lithium. 65. Use the periodic table to determine the number of protons in an atom of barium. 66. How many protons are present in an atom of Be-9?

67. What is the total number of subatomic particles in the nucleus of an atom of Bi?

68. Determine the number of electrons in an atom of iridium. 69. What is the atomic number for an element with 41 neutrons and a mass number of 80? 70. How many electrons are in an atom of gold? 71. What is the mass number for an oxygen atom that has 10 neutrons in its nucleus? 72. How many protons are present in the nuclei of the three known isotopes of hydrogen? 73. Use the periodic table to determine the number of neutrons in nitrogen-14.

74. How many neutrons are present in an atom of the isotope U?

75. Calculate the number of neutrons in Pb.

76. Explain how Dalton improved upon atomic theory more than 2000 years after Democritus’s hypotheses about atoms. 77. Explain how electron microscopy and scanning tunneling microscopes have contributed to the understanding of atoms. 78. What observations by Rutherford led to the hypothesis that atoms are mostly empty space, and that almost all of the mass of the atom is contained in an atomic nucleus? 79. Explain how the atoms of one element differ from those of another element. 80. In what way are two isotopes of the same element different? Explain why isotopes of the same element have the same chemical behavior.