Investigation V: Building with Matter

Transcription

1 Alchemy Unit Investigation V: Building with Matter Lesson 1: You Light Up My Life Lesson 2: Electron Glue Lesson 3: Nobel Gas Envy Lesson 4: Getting Connected Lesson 5: Salty Eights

2 Alchemy Unit Investigation V Lesson 1: You Light Up My Life

3 ChemCatalyst If you were to drop a spoonful of salt, NaCl, into a glass of water, what would happen? If you were to drop a gold ring into a glass of water, what would happen? What do you think is different about the atoms of these two substances? Why wouldn t the individual gold atoms come apart?

4 The Big Question What patterns do we see in the properties of substances?

5 You will be able to: Predict whether MgSO 4 (aq), epsom salts, will conduct electricity.

6

7 Activity Purpose: This lesson allows you to collect evidence regarding some of the properties of substances, and look for patterns. (cont.)

8 Predictions Test Results Substances Conduct? Dissolve? Conduct? Dissolve? Yes/No Yes/No Yes/No Yes/No H 2 O(l), water Yes Al(s), foil aluminum C 12 H 22 O 11 (s), sucrose (sugar) NaCl(s), salt, sodium chloride SiO 2 (s), sand, silicon dioxide C 20 H 42 (s), paraffin (wax) C 2 H 6 O(l), ethanol Cu(s), copper CaCl 2 (s), calcium chloride CuSO 4 (s), copper sulfate

9 (cont.) (cont.)

10 (cont.) Substances that dissolve in water Conduct Don t conduct

11 Making Sense If it is dangerous to take a bath with a blow dryer, what must also be true about the water in the bathtub?

12 Notes Dissolves Yes No Conducts Conducts Yes No Yes No NaCl salt H 2 O water Au gold SiO 2 sand CuCl 2 calcium chloride CuSO 4 copper C 12 H 22 O 11 sugar C 2 H 6 O ethanol Cu copper Al aluminum C 20 H 42 paraffin sulfate

13 Check-In Predict whether MgSO 4 (aq), epsom salts, will conduct electricity. State your reasoning.

14 Wrap-Up Not all substances conduct electricity. Substances that do conduct electricity involve either solid metals, or metalnonmetal compounds dissolved in water. Not all substances dissolve in water.

15 Alchemy Unit Investigation V Lesson 2: Electron Glue

16 ChemCatalyst A gold ring is made up of individual gold atoms. What keeps the atoms together? Why don t the atoms just fall apart from each other? What parts of the atom do you think are responsible for keeping the atoms together in a solid?

17 The Big Question How can we use bonding to explain the properties of substances we encounter?

18 You will be able to: Classify the bonding that occurs in the making of brass.

19 Notes A chemical bond is an attraction between atoms that holds them together in space.

20 Activity Purpose: This lesson helps to explain the physical properties of basic substances by examining the types of bonds that exist between the atoms of these substances. (cont.)

21 (cont.) Ionic Covalent Network Metallic Molecular Covalent (cont.)

22 (cont.) Ionic Covalent Network Metallic Molecular Covalent

23 Making Sense If you have the chemical formula of a substance, how and what can you figure out about it s properties? Explain. Use the compound silver nitrate, AgNO 3, as an example.

24 Notes Model 1: IONIC Properties: Made of metal and non-metal atoms Dissolves in water Conducts electricity when dissolved but not when solid Brittle solids Description of drawing: Spheres without gray areas represent metal atoms. Spheres with gray areas are non-metal atoms. Metal atoms give up their valence electrons to non-metal atoms. (cont.)

25 Notes (cont.) Model 2: COVALENT NETWORK Properties: Made entirely of nonmetal atoms Does not dissolve in water Does not conduct electricity Very hard solids Description of drawing: Valence electrons connect atoms with each other in all directions like a grid or network. (cont.)

26 Notes (cont.) Model 3: METALLIC Properties: Made entirely of metal atoms Do not dissolve in water Conduct electricity Bendable solids Description of drawing: Valence electrons are free to move throughout the substance like a sea of electrons. (cont.)

27 Notes (cont.) Model 4: MOLECULAR COVALENT Properties: Made of nonmetal atoms Some dissolve in water, some do not Do not conduct electricity Tend to be liquids or gases or softer solids Description of drawing: Valence electrons are shared between some atoms. This creates small stable units within the substance. (cont.)

28 Notes (cont.) Atoms which are connected into many identical units are called molecules. They units may be composed of only two atoms or of dozens of atoms. (cont.)

29 Notes (cont.) Dissolves Conducts Yes No Conducts Yes No Yes No NaCl salt H 2 O water Au gold SiO 2 sand CuCl 2 calcium chloride CuSO 4 copper C 12 H 22 O 11 sugar C 2 H 6 O ethanol Cu copper Al aluminum C 20 H 42 paraffin sulfate Ionic Molecular Covalent Metallic Covalent Network

30 Notes (cont.) Metal atoms Non-Metal atoms Metal & Non-Metal atoms Metallic Covalent Network Molecular Covalent Ionic

31 Check-In On the very first day of class, you combined copper with zinc to form brass. How would you classify the bonding in brass? Explain.

32 Wrap-Up A chemical bond is an attraction between atoms involving the valence electrons. There are four types of bonds: ionic, extended covalent, molecular covalent, and metallic.

33 Alchemy Unit Investigation V Lesson 3: Noble Gas Envy

34 ChemCatalyst What type of bonding does this picture represent? What happens to the charge on each atom?

35 The Big Question What ion charges are formed when atoms attain a noble gas electron configuration?

36 You will be able to: Predict what would have to happen for potassium to obtain a noble gas configuration.

37 Notes

38 Activity Purpose: You will explore the ions that are formed when atoms give up and receive electrons from other atoms.

39 Making Sense Why do you think the noble gas configuration is especially stable?

40 Notes A valuable piece of information that can help us predict which ions might be encountered in chemistry: Atoms tend to lose or gain electrons to attain the electron configuration of the noble gas nearest to it on the periodic table. (cont.)

41 (cont.) Atoms with a positive charge are called cations. Atoms with a negative charge are called anions.

42 Check-In Write the electron configuration for potassium, K. What would have to happen for potassium to have a noble gas configuration? Explain.

43 Wrap-Up Noble gases are stable with filled outermost electron shells. Atoms can gain or lose electrons to end up with a noble gas configuration. When atoms lose electrons, they have a positive charge and are called cations. When atoms gain electrons, they have a negative charge and are called anions.

44 Alchemy Unit Investigation V Lesson 4: Getting Connected

45 ChemCatalyst Only certain combinations of elements result in the formation of compounds. Li, lithium, will react with F, fluorine, to form LiF, but it won t form LiF 2 or LiF 3. Mg, magnesium will react with F to form MgF 2, but it won t form MgF or MgF 3. Explain what you think is going on.

46 The Big Question What determines how two elements will combine to form ionic compounds?

47 You will be able to: Use the number of valence electrons to determine which ionic compounds can form.

48 Activity Element 1 (metal) # of valence electrons Element 2 (nonmetal) # of valence electrons compound Na 1 F 7 NaF sodium fluoride Mg O MgO magnesium oxide Mg 2 Cl 7 MgCl 2 magnesium chloride Ne Ne neon total # of valence electrons 8 16 Be F BeF 2 beryllium fluoride

49 Element 1 (metal) # of valence electrons Element 2 (nonmetal) # of valence electrons compound total # of valence electrons MgS magnesium sulfide CaCl 2 calcium chloride Na Br K Se Al N Al O Al 2 O 3 aluminum oxide Al F

50 Making Sense Can you make a rule that helps you predict the composition of compounds that form?

51 Notes Rule of Eight: Ionic compounds tend to form from atoms that together have a total of 8 (or a multiple of 8) electrons in their outermost (valence) shells. This gives each ion a valence electron configuration identical to a noble gas and makes them very stable.

52 Check-In What elements will combine with Sr, strontium, in a one-to-one ratio?

53 Wrap-Up Elements react to form compounds in such a way as to result in 8 electrons in their outermost (valence) shell (or a multiple of eight). Compounds with eight valence electrons are very stable. Noble gases already have eight valence electrons and don t combine with other elements to make new compounds. They are already very stable.

54 Alchemy Unit Investigation V Lesson 5: Salty Eights

55 ChemCatalyst List the compounds you can make with pairs of cards of two different elements. List the compounds you can make with three cards and only two different elements.

56 The Big Question What salts can be formed by combining a metal and a non-metal?

57 You will be able to: Apply the octet rule.

58 Activity Rules for Salty Eights: The point of the game is to make compounds and to be the first to play all of the cards in your hand. These compounds can have two or three or more cards in them, but they can only have two different elements. The game ends when a player uses up all of the cards in his or her hand making compounds. (cont.)

59 (cont.) Shuffle the deck as best as possible. Deal eight cards to each player. The player to the left of the dealer plays first. Using at least two cards from your hand, try to make one compound the valence electrons must add up to eight or a multiple of eight. You must have at least one pink card and one blue card with each compound (the noble gases green cards are an exception and can be played singly). (cont.)

60 (cont.) You must play every turn. In other words you must make one compound each time it is your turn. If you cannot make a compound you must draw from the draw pile until you can put down a compound. When you form a compound during your turn simply place those cards on the table in front of you. As soon as you put down a compound you must name it and then your turn is over. (cont.)

61 (cont.) Play proceeds around the circle until a player uses up all of his or her cards. A player gets 20 points for going out first. Wild cards can be used as any element in that particular group (Wild cards only exist for Groups 1 and 7). The player must identify which element a wild card represents at the time it is played. (cont.)

62 (cont.) Scoring: Every compound played on the table is worth points. The cards left in a person s hand are subtracted. 5 points for every noble gas. 10 points for every compound made out of two cards. 40 points for every compound made out of three cards. (cont.)

63 (cont.) 70 points for every compound made out of four cards. 100 points for every compound made out of five cards. 20 points for going out first. Any player with cards left in his or her hand must count up the number of valence electrons and subtract them from his or her total. (cont.)

64 Metal Nonmetal Compound Formula Compound Name Point value Total

65 Check-In Which of the following compounds are likely to form? (a) Na 2 S (b) K 2 Mg (c) AlBr 2 (d) Na 3 N (e) OCl (f) CaMgO 2

66 Wrap-Up Ionic compounds tend to form from atoms that together have a total of 8 (or a multiple of 8) electrons in their outermost (valence) shells Compounds with eight valence electrons are highly stable. Noble gases already have eight valence electrons and don t combine with other elements to make new compounds. They are already highly stable.

67 Alchemy Unit Investigation V Lesson 6: As Good as Gold

68 ChemCatalyst Name three items that might be on an exam covering the entire Alchemy Unit.

69 The Big Question Can an element be turned into something else?

70 You will be able to: Explain the relationship between compounds, atoms, elements, and the periodic table.

71 Activity Purpose: This lesson provides you with end-of the-unit review and practice. (cont.)

72 (cont.) Element Symbol Atomic No. Group No. # of protons Number of valence electrons Electron configuration oxygen iodine iron radon tungsten lead (cont.)

73 (cont.) Substance Conducts? Yes/No Dissolves in H 2 O? Yes/No Conducts after dissolving? Type of bonding Cu x Zn x brass CSi silicon carbide C 3 H 8 propane CuCl 2 copper chloride

74 Making Sense It is not possible to convert copper into gold in chemical reactions. This can only be done by nuclear reactions, which require the energy of a supernova. Thus, we must resort to using chemistry to create things that are as good as gold.

75 Notes (cont.) a) Investigation I: How do the mass and volume of copper and gold compare? b) Investigation II: Copper and gold have similar properties, but gold is more bendable than copper. Is this consistent with their locations on the periodic table? c) Investigation III: How are copper atoms different from gold atoms? Be specific about the difference in the numbers of atomic particles. (cont.)

76 Notes (cont.) d) Investigation V: The golden penny produced on the first day of this Unit was brass, CuZn. If you wanted to make a substance that is as good as gold, would you choose any elements on the right side of the periodic table? Why or why not?

77 Check-In No Check-In.

78 Wrap-Up No Wrap-Up.