Name: Period: Date: Ms. Randall/Mr. Palermo Unit 2: Atomic Theory Practice Packet 1
A. Atomic Structure Worksheet **Assume all are neutral atoms! Fill in the blanks in the following worksheet. Please keep in mind that the isotope represented by each space may NOT be the most common isotope or the one closest in atomic mass to the value on the periodic table. Atomic Atomic Protons Neutrons Electrons Mass symbol number number C 8 12 24 31 40 30 35 40 89 42 98 W 183 Cr 27 105 71 95 243 83 209 90 142 Md 259 Se 80 40 51 Notice there are two different atoms of zirconium (Zr) listed. They have drastically different mass numbers. What are these two considered to be in relation to one another? 2
B. Atomic Theory- Neutral Atoms and their subatomic parts How many protons, neutrons, and electrons are present in the following neutral atoms? vanadium potassium nitrogen platinum argon helium What is the name of the element that has neutral atoms that contain? 5 protons 16 electrons 17 protons 32 electrons 25 protons 1 electron 82 protons 8 electrons 92 protons 2 electrons 3
C. Complete the following chart: (assume the overall charge on all atoms = 0.except the last one!) Element Symbol Atomic Number # of Protons # of Neutrons Hydrogen 1 Mass Number (amu) # of Electrons He 4 Na 12 Potassium 39 20 20 26 30 Rb 86 Carbon 6 Xenon 131 16 15 At 126 14 7 Copper 64 Ne 10 23 27 Lithium Ion Li + 3 4
D. P, n, e of ions Write the full chemical symbol for the ion with: 1) 12 protons and 10 electrons: 2) 74 protons and 68 electrons: 3) 95 protons and 89 electrons: 4) 33 protons and 36 electrons: Determine the number of p, n, e for the following ions: Cu 2+ Li + O 2- p = n = e = Cl - Al 3+ I 7+ E. Fill in the chart below # protons # electrons # neutrons Atomic # Mass # Lithium 1+ 3 4 Phosphorus 3-18 31 Vanadium 0 23 51 Krypton 0 48 36 Barium 4+ 56 137 Uranium 5-97 146 5
F. Fill in the chart below. ATOM or ION? PROTONS NEUTRONS ELECTRONS MASS NUMBER NUCLEAR CHARGE Al +3 37 Cl 23 Na +1 He 15 O -2 14 C C Au +3 U 222 Rn Cu +1 Cu +2 Question: Which of the above atoms are isotopes of one another? Explain how you know this. 6
G. Complete the following table: Substance Atomic # Mass # Protons Electrons Neutrons 64 Cu +2 8 17 10 32 32 41 14 C 30 28 35 3 Li +1 N 24 17 28 18 S +2 7
H. For the following atoms/ions determine the number of protons, neutrons, electrons, mass number, and nuclear charge. ATOM or ION? PROTONS NEUTRONS ELECTRONS MASS NUMBER NUCLEAR CHARGE 15 N Cu +2 8 B +3 17 O F -1 206 Pb 208 Pb Ag +1 Zn +2 Mg S -2 Question: Which of the above atoms are isotopes of one another? Explain how you know this. 8
I. Calculate the atomic mass of each of the following isotopes. SHOW ALL WORK. Element Mass Percent Abundance 1) copper-63 62.9396 amu 69.17% copper-65 64.9278 amu 30.83% 2) uranium-235 235.0439 amu 0.72% uranium-238 238.0510 amu 99.28% 3) hydrogen-1 1.0078 amu 99.985% hydrogen-2 2.0140 amu 0.015% 4) element Q-8 8 amu 10.0% element Q-9 9 amu 20.0% element Q-10 10 amu 70.0% 9
J. Weighted Averages HW SHOW ALL WORK *You can round the masses given to you or use them as given just be consistent! 1) Element X exists in three isotopic forms. The isotopic mixture consists of 10.0% 10 X, 20.0% 11 X, and 70.0% 12 X. What is the average atomic mass of this element? 2) Element Y exists in three isotopic forms. The Isotopic mixture consists of 15.0% 21 X, 65.0% 22 X, and 20.0% 23 X. That is the average atomic mass of this element? 3) A mystery element occurs in nature as two isotopes. Isotope A has a mass of 10.0130 amu and its abundance is 19.9%; Isotope B has a mass of 11.0093 amu and its abundance is 80.1%. From this data, calculate the atomic mass of the element and show all work. Lastly, identify the element. 4) A mystery element occurs in nature as two isotopes. Isotope A has a mass of 62.939598 amu and its abundance is 69.17%; Isotope B has a mass of 64.927793 amu and its abundance is 30.83%. From this data, calculate the atomic mass of the element and show all work. Lastly, identify the element. 10
5) A mystery element occurs in nature as three isotopes. Isotope A has a mass of 15.994915 amu and its abundance is 99.762%; Isotope B has a mass of 16.999132 amu and its abundance is 0.0380%; Isotope C has a mass of 17.999160 amu and its abundance is 0.2000%. From this data, calculate the atomic mass of the element and show all work. Lastly, identify the element. K. Isotopes and Average Atomic Mass Example: A sample of cesium is 75% 133 Cs, 20% 132 Cs, and 5% 134 Cs. What is the average atomic mass? Determine the average atomic mass of the following mixtures of isotopes. 1. 80% 127 I, 17% 126 I, 3% 128 I 2. 50% 197 Au, 50% 198 Au 3. 15% 55 Fe, 85% 56 Fe 11
4. 99% 1 H, 0.8% 2 H, 0.2% 3 H 5. 95% 14 N, 3% 15 N, 2% 16 N 6. 98% 12 C, 2% 14 C 12
L. Construct Bohr diagrams for the following: Na F electron configuration electron configuration O Li + electron configuration electron configuration Cl - Ne electron configuration electron configuration 13
M. Draw Lewis Dot Diagrams for the following: N C Li + He O B S Kr Se 2- Ca +2 14
N. Electron Configuration Worksheet For the questions 1-10, assume all atoms are neutral. Based on the electron configurations given, determine the identity of the element and whether it is in the ground or excited state. Electron Configuration Identity Ground/Excited 1. 2-8-1 2. 2-8-16-3 3. 2-8-2 4. 2-7-8 5. 1-3 6. 2-8-6 7. -18-32-18-4 8. -18-32-17-3 9. 2-7 10. 1-8 Give an electron configuration for the following: 11. Sulfur in its ground state. 12. Helium in an excited state. 13. When atoms of an element are emitting a certain wavelength (or color) of light, it means that a) the atoms have gained energy and electrons have jumped to an excited state. b) the atoms have gained energy and electrons have fallen back to the ground state. c) the atoms have lost energy and electrons have fallen back to the ground state. d) the atoms have lost energy and electrons have jumped to an excited state. 15
Use the emissions spectra results below to answer questions 14 and 15: Gas A Gas B Gas C Gas D Unknown Gas 14. According to these experimental spectra results, the unknown gas is a mixture of which gases? 15. Each line on the visible light spectrum for the gases above represents a) electrons jumping to the same excited state or energy level. b) electrons falling back down to their ground state from the same energy level. c) electrons jumping to multiple excited states or energy levels. d) electrons falling back down to their ground state from multiple energy levels. 16