Unit 3 Atomic Structure

Transcription

1 Name: Unit 3 Atomic Structure Scientist Year Contribution and/ or Experimental Work Democritus Aristotle Alchemists Boyle Franklin Dalton Avogadro Mendeleev Moseley 1

2 Scientist Year Contribution and/ or Experimental Work Curies Thomson Millikan Goldstein Rutherford Chadwick Bohr Schroedinger. 2

3 Atomic Number Gridsheet Fill in the missing numbers in the following table. Atomic Number (Z) Mass Number (p + + n 0 ) protons (p + ) neutrons (n 0 ) electrons (e - ) Symbol Atomic Number (Z) Mass Number (p + + n 0 ) protons (p + ) neutrons (n 0 ) electrons (e - ) Symbol

4 Atomic Number (Z) Mass Number (p + + n 0 ) protons (p + ) neutrons (n 0 ) electrons (e - ) Symbol Atomic Number (Z) Mass Number (p + + n 0 ) protons (p + ) neutrons (n 0 ) electrons (e - ) Symbol

5 Calculating Average Atomic Mass 1. Naturally occurring chlorine is 75.53% 35 Cl, which has an atomic mass of amu, and 24.47% 37 Cl, which has an atomic mass of amu. Calculate the average atomic mass of chlorine. 2. Three isotopes of silicon occur in nature: 28 Si (92.21%), which has a mass of amu, 29 Si (4.70%) which has a mass of amu; and 30 Si (3.09%), which has a mass of amu. Calculate the average atomic mass of silicon. 3. The element neon consists of three isotopes with masses 19.99, 20.99, and amu. These three isotopes are present in nature to the extent of 90.92, 0.25, and 8.83 percent by mass, respectively. Find the average atomic mass of neon. 4. The element silver consists in nature of two isotopes, 107 Ag with atomic mass amu, and 109 Ag with atomic mass amu. The percent abundances are and respectively. Calculate the average atomic mass of silver. 5. Calculate the average atomic mass of potassium given potassium is 93.12% K-39 and 6.88% K-41. The atomic mass of the two isotopes is amu and amu, respectively. 6. Boron has two isotopes B-10 (19.78%) and B-11 (80.22%). The atomic mass of B-10 is amu and the atomic mass of B-11 is amu. Calculate the average atomic mass of boron. 7. Challenge : Gallium consists of two naturally occurring isotopes Ga-69 and Ga-71with masses of and amu, respectively. Calculate the % abundance of each isotope of Gallium. 5

6 Bohr Diagrams 6

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8 Name: Element Flashcards Your next quiz will be to learn the name and symbol for the first 20 elements including the average atomic mass to 3 significant figures. Spelling will count! Your assignment is to prepare flashcards with the name of each element on one side and its symbol and atomic mass of the other. You may then begin quizzing yourself or a partner as a way to study. Name Symbo Atomic Name Symbol Atomic l Mass Mass 1. Hydrogen H Sodium Na Helium He Magnesium Mg Lithium Li Aluminum Al Beryllium Be Silicon Si Boron B Phosphorus P Carbon C Sulfur S Nitrogen N Chlorine Cl Oxygen O Argon Ar Fluorine F Potassium K Neon Ne Calcium Calciu m

9 Next set of 25 elements. You need to know the name (with correct spelling!) and symbol for each. Name Mercury Radon Bismuth Barium Cobalt Tin Manganese Nickel Platinum Iron Bromine Titanium Arsenic Lead Gold Silver Copper Radium Iodine Zinc Chromium Uranium Plutonium Scandium Vanadium Symbol Hg Rn Bi Ba Co Sn Mn Ni Pt Fe Br Ti As Pb Au Ag Cu Ra I Zn Cr U Pu Sc V 9

10 The World of Chemistry Episode 7 - The Periodic Table 1. What two types of properties are described in the video? 2. What are some examples of physical properties? 3. How many elements are on the modern periodic table? How many of these can be found in nature? 4. Why do the symbols for some elements (such as iron) seem to have no relationship to their name? 5. What is meant by the atomic and mass number of an element? 6. Elements in the periodic table are arranged by increasing number. 7. What is a groups of elements? a period? 10

11 8. What are the ingredients used in the making of glass? What determines the color of glass? 9. What are alkali metals? Describe their reaction with water. 10. How does the size of an atom change - a. as you go down a group of elements? b. as you go from left to right in a period of elements? 11. Who developed the periodic table? 12. What did Mendeleev do for elements that had not yet been discovered? 13. How did Glenn Seaborg change the periodic table? 14. Why are the electrons in the outer shell of an atom important? 11

12 Fill in information for each family on the periodic table. Family Location Properties/Characteristics/Uses on table Hydrogen Alkali metals Alkaline Earth-meta ls Transition Metals Boron Family Carbon Family 12

13 Family Nitrogen Family Location on table Properties/Characteristics/Uses Oxygen, Family Halogens Noble Gases Rare Earth 13

14 Mendeleev for a Day Introduction As more and more elements were discovered during the 1800s, chemists began to categorize them according to similarities in chemical and physical properties. A Russian chemist, Dmitri Mendeleev ( ) was more successful than most. He arranged the elements in vertical columns in order of increasing atomic mass. The columns were then arranged so that elements with similar chemical properties were placed side by side. Mendeleev left numerous spaces in his table because there were no known elements with the appropriate properties to fill the spaces. He then predicted the properties of these unknown elements based on the properties of the elements next to them on the periodic table. When these missing elements were discovered, they were found to have properties very similar to those predicted by Mendeleev. Like Mendeleev, in this investigation you will group unknown elements (contained in compounds dissolved in water to make solutions) according to their chemical behaviors. You will see if a precipitate (solid substance) forms when two solutions are mixed together. You then will observe which precipitates are dissolved by an acidic solution. Finally, you will record any color changes that occur when the solution is mixed with an acid-base indicator. After analyzing your data, you will place each unknown solution into a group with other solutions of similar characteristics and thereby group elements together based on chemical properties like Mendeleev. Procedure 1. Put on safety goggles. 2. Label three test tubes A, B, and C with a marking pencil. Using a graduated cylinder, obtain 3 ml of Solution #1. Place 1 ml of Solution #1 into each test tube A,B, and C. 3. To test tube A, add 12 drops of test Solution A. 4. To test tube B, add 12 drops of test Solution B. 5. To test tube C, add 12 drops of test Solution C. 6. Any test tube that does not show an immediate change should be stirred for at least 10 seconds. Rinse the stirring rod after each use. Record all results in the Data Table. 7. To any test tube that contains a precipitate, add 20 drops of test Solution D and stir for at least 15 seconds. Rinse the stirring rod after each use. Record all results. 14

15 8. Pour the solution in test tube A into a labeled waste container provided by your teacher. Rinse out the test tubes and graduated cylinder thoroughly for use in the next set of tests. 9. Repeat Steps 2 through 8 for each of the other solutions #1-#9. When you are done testing solutions #4 and #9, put the waste material into the labeled waste containers provided by your teacher. 10. Clean up your work area and wash your hands before leaving the lab. Observations DATA TABLE Reactions of Unknown Solutions Record your observations in the data table below. For A and B be sure to indicate if a precipitate forms and describe its appearance (color, consistency, etc.) Unknown A-ppt? B-ppt? C-color? D-Dissolved?

16 9 Pre-Lab Discussion 1. How does Mendeleev s periodic table differ from the modern periodic table? 2. Why did Mendeleev leave blank spaces on his periodic table? Did later discoveries justify his predictions? 3. Why is it necessary to mix any solution that does not show an immediate change? 4. Why is it necessary to rinse each test tube thoroughly between trials? 5. Which solutions need to be disposed of in a special container? Mendeleev s Periodic Table 16

17 Conclusions : 1. Why do you think that this investigation is titled Mendeleev for a Day? 2.Based on the observations from your partnership, group the nine solutions into families based upon their chemical behavior with the reagents. No single solution should be in a group by itself. Justify your groupings based on observations in the space below. 3. Did the solution forming a yellow precipitate with A get grouped with an unknown forming a white precipitate with A? Do you think that this is the best conclusion? Why or why not? 17

18 4. One of the reagents was an acid/base indicator. Indicators have one color in the presence of an acid and another color in the presence of a base. Which reagent was the indicator? 5.Suppose you could do experiments with your unknowns in which you reacted each of them with oxygen to form an oxide, as Mendeleev did. How would this information help you determine the location of the compounds in the periodic table? 6.No members of Group 18 can be found on Mendeleev s version of the table. Suggest an explanation for their absence. 18

19 Name: Build an Atom 1.List the location, charge, and mass of the three major particles in the atom. 2. Develop a relationship ( in the form of a single sentence or equation) that can predict the charge of an atom based on the number and types of particle. 3. What is the rule for determining the mass number of an atom or ion? 4. Explain the meaning of a,b,c, and d in the nuclear notation for an atom below. 19

20 5. Define the following terms: Element Symbol Charge Atomic Number Mass number 6. Which particle affects the stability of the atom? 7. List the requirements for two atoms to be isotopes of each other. 20

21 8. Can you tell from the periodic table exactly how many neutrons are in an atom? Explain your answer. 9. How does an atom become a cation? 10. How does an atom become an anion? 11. What do an atom, ion, and isotope of an element have in common? 12. Do atoms, ions, and isotopes behave the same chemically? Explain. 21

22 Name Symbol Atomic number Mass number Number of n 0 Number of e - Charge sodium Carbon Carbon Carbon Carbon Carbon argon

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