Atomic Regents Review

Transcription

1 Name: Atomic Regents Review Date: Base your answers to questions 1 through 4 on the information below and on your knowledge of chemistry. A student compares some models of the atom. These models are listed in the table below in order of development from top to bottom. 1. State one way in which the Bohr model agrees with the Thomson model. 2. Using the conclusion from the Rutherford model, identify the charged subatomic particle that is located in the nucleus. 3. State one conclusion about the internal structure of the atom that resulted from the gold foil experiment. 4. State the model that first included electrons as subatomic particles. Page 1

2 Base your answers to questions 5 through 7 on the information below. The bright-line spectra for three elements and a mixture of elements are shown below. 5. State the total number of valence electrons in a cadmium atom in the ground state. 6. Identify all the elements in the mixture. 7. Explain, in terms of both electrons and energy, how the bright-line spectrum of an element is produced. 8. Explain, in terms of protons and neutrons, why U-235 and U-238 are different isotopes of uranium. 9. Copper has two naturally occurring isotopes. Information about the two isotopes is shown in the table below. In the space in your answer booklet, show a numerical setup for calculating the atomic mass of copper. 10. in the space below, write an electron configuration for a silicon atom in an excited state. Base your answers to questions 11 and 12 on the information below. In the gold foil experiment, a thin sheet of gold was bombarded with alpha particles. Almost all the alpha particles passed straight through the foil. Only a few alpha particles were deflected from their original paths. 11. Explain, in terms of charged particles, why some of the alpha particles were deflected. Page 2

3 12. State one conclusion about atomic structure based on the observation that almost all alpha particles passed straight through the foil. Base your answers to questions 13 and 14 on the information below An atom in an excited state has an electron configuration of Explain, in terms of subatomic particles, why this excited atom is electrically neutral. 14. Write the electron configuration of this atom in the ground state. Base your answer to the following question on the information below. Carbon has three naturally occurring isotopes, C-12, C-13, and C-14. Diamond and graphite are familiar forms of solid carbon. Diamond is one of the hardest substances known, while graphite is a very soft substance. Diamond has a rigid network of bonded atoms. Graphite has atoms bonded in thin layers that are held together by weak forces. Recent experiments have produced new forms of solid carbon called fullerenes. One fullerene, C 60, is a spherical, cagelike molecule of carbon. 15. Determine both the total number of protons and the total number of neutrons in an atom of the naturally occurring carbon isotope with the largest mass number. 16. Describe the electrons in an atom of carbon in the ground state. Your response must include: the charge of an electron the location of electrons based on the wave-mechanical model the total number of electrons in a carbon atom Base your answers to questions 17 through 19 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 Compare the abundance of the two naturally occurring isotopes of boron. 18. State, in terms of subatomic particles, one difference between the nucleus of a carbon-11 atom and the nucleus of a boron-11 atom. 19. 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. Page 3

4 Base your answers to questions 20 and 21 on the information below. In 1897, J. J. Thomson demonstrated in an experiment that cathode rays were deflected by an electric field. This suggested that cathode rays were composed of negatively charged particles found in all atoms. Thomson concluded that the atom was a positively charged sphere of almost uniform density in which negatively charged particles were embedded. The total negative charge in the atom was balanced by the positive charge, making the atom electrically neutral. In the early 1900s, Ernest Rutherford bombarded a very thin sheet of gold foil with alpha particles. After interpreting the results of the gold foil experiment, Rutherford proposed a more sophisticated model of the atom. 20. State one aspect of the modern model of the atom that agrees with a conclusion made by Thomson. 21. State one conclusion from Rutherford's experiment that contradicts one conclusion made by Thomson. 22. In the box below, draw a Lewis electron-dot diagram for an atom of boron. Base your answer to the following question on the information below and on your knowledge of chemistry. Illuminated EXIT signs are used in public buildings such as schools. If the word EXIT is green, the sign may contain the radioisotope tritium, hydrogen-3. The tritium is a gas sealed in glass tubes. The emissions from the decay of the tritium gas cause a coating on the inside of the tubes to glow. 23. State, in terms of neutrons, how an atom of tritium differs from an atom of hydrogen-1. Base your answers to questions 24 and 25 on the information below. A fluorescent light tube contains a noble gas and a drop of mercury. When the fluorescent light operates, the Hg is a vapor and there are free-flowing Hg ions and electrons in the tube. The electrons collide with Hg atoms that then emit ultraviolet (UV) radiation. The inside of the tube is coated with a mixture of several compounds that absorbs UV radiation. Ions in the coating emit a blend of red, green, and blue light that together appears as white light. The compound that produces red light is Y2O3. The compound that produces green light is CeMgAl11O19. The compound that produces blue light is BaMgAl10O Write the chemical name of the compound that produces red light. 25. Explain, in terms of both electrons and energy, how ions in the coating emit light. Page 4

5 26. Determine the mass number of the magnesium atom represented by the electron-shell diagram. Base your answer to the following 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. 27. Show a correct numerical setup for calculating the atomic mass of Si. Page 5

6 Base your answer to the following question on the information below The Balmer series refers to the visible bright lines in the spectrum produced by hydrogen atoms. The color and wavelength of each line in this series are given in the table below. 28. On the diagram above draw four vertical lines to represent the Balmer series. Page 6

7 Base your answers to questions 29 and 30 on the following information. In a laboratory, a glass tube is filled with hydrogen gas at a very low pressure. When a scientist applies a high voltage between metal electrodes in the tube, light is emitted. The scientist analyzes the light with a spectroscope and observes four distinct spectral lines. The table below gives the color, frequency, and energy for each of the four spectral lines. The unit for frequency is hertz, Hz. 29. Explain, in terms of subatomic particles and energy states, why light is emitted by the hydrogen gas. 30. On the grid, plot the data from the data table for frequency and energy. Circle and connect the points, including the point (0,0) that has already been plotted and circled for you. Page 7