Unit 3 Atomics Repair Problems

Transcription

1 1. What is the charge of the nucleus in an atom of oxygen-17? A) 0 B) 2 C) +8 D) A neutral atom contains 12 neutrons and 11 electrons. The number of protons in this atom is A) 1 B) 11 C) 12 D) What is the total number of protons contained in the nucleus of a carbon-14 atom? A) 6 B) 8 C) 12 D) What is the total number of neutrons in the nucleus of a neutral atom that has 19 electrons and a mass number of 39? A) 19 B) 20 C) 39 D) What is the mass number of an atom that has six protons, six electrons, and eight neutrons? A) 6 B) 12 C) 14 D) The mass of a calcium atom is due primarily to the mass of its A) protons, only B) neutrons, only C) protons and neutrons D) protons and electrons 7. The nucleus of an atom of cobalt-58 contains A) 27 protons and 31 neutrons B) 27 protons and 32 neutrons C) 59 protons and 60 neutrons D) 60 protons and 60 neutrons 8. All the isotopes of a given atom have A) the same mass number and the same atomic number B) the same mass number but different atomic numbers C) different mass numbers but the same atomic number D) different mass numbers and different atomic numbers 9. Which diagram represents the nucleus of an atom of? A) B) C) D) 10. Which two nuclides are isotopes of the same element? A) B) C) D) 11. The atomic mass of element A is 63.6 atomic mass units. The only naturally occurring isotopes of element A are A-63 and A-65. The percent abundances in a naturally occurring sample of element A are closest to A) 31% A-63 and 69% A-65 B) 50% A-63 and 50% A-65 C) 69% A-63 and 31% A-65 D) 100% A-63 and 0% A A gram sample of naturally occurring boron contains grams of boron-10 (atomic mass = atomic mass units) and grams of boron-11 (atomic mass = atomic mass units). Which numerical setup can be used to determine the atomic mass of naturally occurring boron? A) (0.1978)(10.01) + (0.8022)(11.01) B) (0.8022)(10.01) + (0.1978)(11.01) C) (0.1978)(10.01)/(0.8022)(11.01) D) (0.8022)(10.01)/(0.1978)(11.01) 13. Which statement best explains why most atomic masses on the Periodic Table are decimal numbers? A) Atomic masses are determined relative to an H 1 standard. B) Atomic masses are determined relative to an O 16 standard. C) Atomic masses are a weighted average of the naturally occurring isotopes. D) Atomic masses are an estimated average of the artificially produced isotopes.

2 14. What is the electron configuration of a sulfur atom in the ground state? A) 2 4 B) 2 6 C) D) Which electron configuration represents the electrons in an atom of chlorine in an excited state? A) B) C) D) An electron in an atom moves from the ground state to an excited state when the energy of the electron A) decreases B) increases C) remains the same 17. Which electron configuration represents the electrons of an atom in an excited state? A) B) C) D) As an electron in an atom moves from the ground state to the excited state, the electron A) gains energy as it moves to a higher energy level B) gains energy as it moves to a lower energy level C) loses energy as it moves to a higher energy level D) loses energy as it moves to a lower energy level 19. In the wave-mechanical model, an orbital is a region of space in an atom where there is A) a high probability of finding an electron B) a high probability of finding a neutron C) a circular path in which electrons are found D) a circular path in which neutrons are found 20. Draw a Lewis electron-dot diagram for a sulfur atom in the ground state. 21. Base your answer to the following question on the information below. A glass tube is filled with hydrogen gas at low pressure. An electric current is passed through the gas, causing it to emit light. This light is passed through a prism to separate the light into the bright, colored lines of hydrogen's visible spectrum. Each colored line corresponds to a particular wavelength of light. One of hydrogen's spectral lines is red light with a wavelength of 656 nanometers. Tubes filled with other gases produce different bright-line spectra that are characteristic of each kind of gas. These spectra have been observed and recorded. Explain, in terms of electron energy states and energy changes, how hydrogen's bright-line spectrum is produced.

3 22. Base your answer to the following question on the information below. An atom has an atomic number of 9, a mass number of 19, and an electron configuration of Explain why the number of electrons in the second and third shells show that this atom is in an excited state. 23. In the early 1900s, experiments were conducted to determine the structure of the atom. One of these experiments involved bombarding gold foil with alpha particles. Most alpha particles passed directly through the foil. Some, however, were deflected at various angles. Based on this alpha particle experiment, state two conclusions that were made concerning the structure of an atom. 24. Base your answer to the following question on the diagram below, which represents an atom of magnesium-26 in the ground state. Write an appropriate number of electrons in each shell to represent a Mg-26 atom in an excited state. Your answer may include additional shells. 25. Base your answer to the following question on the information below. Naturally occurring elemental carbon is a mixture of isotopes. The percent composition of the two most abundant isotopes is listed below % of the carbon atoms have a mass of atomic mass units. 1.07% of the carbon atoms have a mass of atomic mass units. Describe, in terms of subatomic particles found in the nucleus, one difference between the nuclei of carbon-12 atoms and the nuclei of carbon-13 atoms. The response must include both isotopes.

4 26. Base your answer to the following 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. Explain the production of an emission spectrum in terms of the energy states of an electron.

5 Answer Key Unit 3 Atomics Repair Problems 1. C 2. B 3. A 4. B 5. C 6. C 7. A 8. C 9. B 10. C 11. C 12. A 13. C 14. D 15. B 16. B 17. C 18. A 19. A Examples: The electron of hydrogen absorbs energy and jumps to a higher energy state. The excited electron returns to a lower energy state, releasing light energy The e absorbs energy and jumps to a higher level. The e falls back to a lower level and releases energy related to a particular color. 22. 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 The nucleus is small. The nucleus is positively charged. The atom is mostly empty space. The nucleus is dense Responses include, but are not limited to: Carbon-12 has six neutrons and carbon-13 has seven neutrons Carbon-13 has one more neutron than carbon-12 C-12 has 6n, C-13 has 7n. 26. Acceptable responses: Energy is released when an electron falls from a high state (excited) to a low state (ground), excited state to ground state, high energy to low energy.