Transcript Chapter 3
Chapter 3 Chemical Compounds Types of Compounds 2 Inorganic Compounds – do not contain carbon Organic Compounds – contain carbon 7/21/2015 HFinks '07 Inorganic Compounds 3 Ionic compound combination of metals and nonmetals made up of positive and negative ions joined together by electrostatic forces 7/21/2015 HFinks '07 Ions 4 Ions are atoms that have either lost or gained electrons. Electrons are lost from the outermost energy level (discussed later in textbook) Ions that have more protons than electrons are positively charged Ions that have more electrons than protons are negatively charged 7/21/2015 HFinks '07 Monatomic Ions Formed from a single atom Example: Sodium Sulfur 5 Na+ s6+ or S2- 7/21/2015 HFinks '07 Monatomic ions 6 Ions formed from a single atom Atom = Na Ion = Na+ Atom = O Ion = O2- 7/21/2015 HFinks '07 Using your periodic table 7 The number of the main group elements will be used to determine the oxidation states. Groups IA, IIA, IIIA = +, 2+, 3+ Group VA = 5+, 3Group VIA = 6+, 2Group VIIA = 7+, 7/21/2015 HFinks '07 Alkali Metals (Group IA) The oxidation number of alkali metals in a compound is always 1+. Never write the number 1 for anything in chemistry. It is understood. 8 7/21/2015 HFinks '07 Alkaline Earth Metals (Group IIA) 9 The oxidation number of alkaline earth metals in a compound is always 2+. 7/21/2015 HFinks '07 Nitrogen Family (Group VA) Nitrides, phosphides, and arsenides are always 3- in binary salts. N3- 10 P3- 7/21/2015 As3- HFinks '07 Oxygen Family (Group VIA) The oxidation number of oxygen is almost always 2- in a compound. There are exceptions. a) Peroxides, O22- (each oxygen is 1-) [Formed with elements in Groups IA and IIA] b) Superoxides, O2- (each oxygen is ½-) K, Rb and Ce are the only elements that form Superoxides. 11 Sulfide, selenide, telluride, and polonide are always 22-, Se2-, Te2-, Po2-) in binary salts. (S7/21/2015 HFinks '07 The Halogens (Group VIIA) 12 In metallic halides the halogen (F, Cl, Br, I, At) always has an oxidation number equal to 1 -. Remember: Never write the number 1. 7/21/2015 HFinks '07 Oxidation States for Monatomic Ions Atom Oxidation State Hydrogen (+) and (-) Sodium Barium Aluminum oxygen 13 7/21/2015 HFinks '07 Oxidation State for Monatomic Ions 14 Atom Oxidation State Hydrogen (+) and (-) H+, H- Sodium Na+ Barium Ba2+ Aluminum Al 3+ oxygen O2- 7/21/2015 HFinks '07 Balancing Using Oxidation Number 15 The oxidation number of any element in its free state (uncombined with other elements) is 0. 7/21/2015 HFinks '07 Ionic Compounds 16 Ionic compounds consists of a metallic ion and a non-metallic ion. Positive ion is the cation Negative ion is the anion. 7/21/2015 HFinks '07 Chemical Formula indicates 17 The elements present The relative number of atoms of each element in the compound 7/21/2015 HFinks '07 Binary Compounds Binary compounds are made of two different element. -Combined chemically -Definite proportion by mass 18 7/21/2015 HFinks '07 Balancing Binary Compounds Step I: Write the symbols for each ion Example: Na Cl Step II: Assign an oxidation number Na+ Cl- Step III: Balance the compound. The sum of the oxidation numbers must be zero. (Hint: Crisscross the charges. Don’t include the signs.) NaCl 19 Al3+ S2- 7/21/2015 Al2S3 HFinks '07 Balancing Binary Compounds What should you do if the charges are the same? Nothing. The formula is balanced. The sum of the charges is “0”. 20 Example: Ba 2+ O27/21/2015 = BaO HFinks '07 Balancing Binary Formulas 21 Silver & chlorine Zinc & oxygen Calcium & bromine Strontium & fluorine Barium & chlorine Calcium & chlorine 7/21/2015 HFinks '07 Balancing Binary Formulas 22 Silver & chlorine Zinc & oxygen Calcium & bromine Strontium & fluorine Barium & chlorine Calcium & chlorine 7/21/2015 AgCl ZnO CaBr2 SrF2 BaCl2 CaCl2 HFinks '07 Naming Binary Compounds 1. Write a balanced formula 2. Write the name of the 1st ion with no changes. 3. Change the ending on the 2nd ion to –ide. 23 7/21/2015 HFinks '07 Naming Binary Compounds Example NaCl = sodium chloride 24 7/21/2015 HFinks '07 Naming Binary Compounds 25 Silver & chlorine Zinc & oxygen Calcium & bromine Strontium & fluorine Barium & chlorine Calcium & chlorine 7/21/2015 HFinks '07 Naming Binary Compounds 26 Silver & chlorine Zinc & oxygen Calcium & bromine Strontium & fluorine Barium & chlorine Calcium & chlorine 7/21/2015 silver chloride zinc oxide calcium bromide strontium fluoride barium chloride calcium chloride HFinks '07 Transitional Ions and Charges 27 Fe2+ Iron (II) Fe3+ Iron (III) Ni 2+ Ni 3+ Au+ Au 3+ Sn2+ Tin (II) Sn4+ Tin (IV) Zn 2+ Ag+1 Cu+1 Copper (I) Cu+2 Copper (II) Pb 2+ Pb 4+ Mn+2, +3, +4,+6,+7 Co +2 Co +3 7/21/2015 HFinks '07 Naming Transitional Binary Compounds 28 Fe2+ Iron (II) Fe3+ Iron (III) FeCl2 = iron (II) chloride Sn2+ Tin (II) Sn4+ Tin (IV) SnCl2 = tin (II) chloride Cu+1 Copper (I) Cu+2 Copper (II) CuCl = copper (I) chloride 7/21/2015 HFinks '07 Polyatomic Ions 29 Polyatomic ions consist of two or more ions that act as one in a chemical reaction. Examples: NO3nitrate PO43- phosphate SO42- sulfate NO2- nitrite SO32- sulfite OH- hydroxide ClO3- chlorate MnO4- permanganate C2H3O2- acetate NH4+ ammonium 7/21/2015 HFinks '07 Ternary Compounds Ternary compounds are made up of three ions. Two of the ions are joined together and act as one. (polyatomic ion) Example: Na = sodium 30 NaNO3 N = nitrogen O = oxygen N & O make up the nitrate ion, NO37/21/2015 HFinks '07 Naming Ternary Compounds 1. Write a balanced formula 2. Write the name of the 1st ion. No changes to name. 3. Write the name of the polyatomic ion. 31 NaNO3 = sodium nitrate 7/21/2015 HFinks '07 Formula and Name of Ternary Compounds 32 MgCO3 Pb(NO3)2 Ca(OH)2 Ba(NO3)2 Fe2(SO4)3 LiC2H3O2 KClO3 (NH4)2SO4 magnesium carbonate lead nitrate calcium hydroxide barium nitrate iron (III) sulfate lithium acetate potassium chlorate ammonium sulfate 7/21/2015 HFinks '07 Organic Compounds Molecular compound Made up of a small number of different non-metal atoms - Held together by forces known as covalent bonds The chemical formula gives you the number of atoms of each element contained in a single molecule of the compound – 33 7/21/2015 HFinks '07 Organic Compounds Prefixes Number 1 2 3 4 5 6 7 8 9 10 34 Prefix monodi-/bi tritetrapentahexaheptaoctanonadeca7/21/2015 HFinks '07 Organic Compounds 35 Carbon dioxide CO2 Nitrogen trioxide NO3 Dinitrogen trioxide N2O3 7/21/2015 HFinks '07 Nomenclature Review Wkst. 36 1. calcium chloride 2. magnesium oxide 2. MgCl2 3. iron (III) hydroxide 3. BaF2 4. potassium sulfate 4. KNO3 5. cesium nitrate 5. Al2S3 7/21/2015 1. NaCl HFinks '07 Nomenclature Review 37 6. rubidium selenide 6. Li2O 7. strontium phosphate 7. SrSO4 8. potassium oxide 8. CuCl2 9. copper (I) oxide 9. (NH4)3PO4 10. ammonium sulfafte 10. BeBr2 7/21/2015 HFinks '07 Nomenclature Review 38 11. sodium sulfide 11. H2SO4 12. rubidium sulfate 12. Mg3(PO4)2 13. calcium hydroxide 13. Na3PO4 14. sodium iodide 14. (NH4)2O 15. potassium hydroxide 15. AuCl3 7/21/2015 HFinks '07 Nomenclature Review 39 16. lead (II) sulfide 16. Na2CO3 17. sodium carbonate 17. SiO2 18. iron (III) chloride 18. PbS 19. phosphoric acid 19. N2O3 20. barium sulfate 20. HNO3 21. silver nitrate 21. CaBr2 7/21/2015 HFinks '07 Naming Ionic Compounds 40 1. sodium carbonate 129.0 g/mol 2. sodium hydroxide 40.00 g/mol 3. magnesium bromide 184.1 g/mol 4. potassium chloride 74.6 g/mol 5. iron (II) chloride 126.8 g/mol 7/21/2015 HFinks '07 Naming Ionic Compounds 41 6. iron (III) chloride 162.3 g/mol 7. zinc hydroxide 99.4 g/mol 8. beryllium sulfate 114.1 g/mol 9. chromium (II) fluoride 90.0 g/mol 10. aluminum sulfide 150 g/mol 7/21/2015 HFinks '07 Naming Ionic Compounds 42 11. lead (II) oxide 223.2 g/mol 12. lithium phosphate 115.7 g/mol 13. titanium (IV) iodide 556.3 g/mol 14. cobalt (II) nitride 204.7 g/mol 15. magnesium phosphide 134.9 g/mol 7/21/2015 HFinks '07 Naming Ionic Compounds 43 16. gallium nitrite 207.7 g/mol 17. silver sulfite 296 g/mol 18. ammonium hydroxide 35.0 g/mol 19. aluminum cyanide 105.0 g/mol 20. beryllium acetate 127.0 g/mol 7/21/2015 HFinks '07 Polyatomic Ions 44 Don’t separate the elements in the ion. Keep them together. Don’t: N + O3 But NO3- 7/21/2015 HFinks '07 Determining the Charge on a Polyatomic Ion 45 (NO3) - ( N5+ O36-)- (SO4)2- (S6+ O48-)2- 7/21/2015 HFinks '07 Determine the oxidation number of the ions in the polyatomic ions below 46 Phosphate Chlorate Sulfite Permanganate Nitrite Hyroxide 7/21/2015 HFinks '07 Oxidation States of Elements in Polyatomic Ions 47 Phosphate (P5+ O4 8-) 3- Chlorate (Cl5+ O36-) – Sulfite (S4+ O36- ) 2- Hydroxide (O2-, H+)7/21/2015 HFinks '07 Oxidation States of Elements in Polyatomic Ions 48 (Mn 7+ O42-) - Permanganate Nitrite (N 5+ O24-) – Acetate (C26+H33-O24-) – 7/21/2015 HFinks '07 What are the oxidation states of the atoms below? 49 Sodium Magnesium Barium Potassium Aluminum Calcium chlorine oxygen sulfur fluoride bromine iodine 7/21/2015 HFinks '07 Oxidation States for Monatomic Ions Atom Oxidation State Chlorine Sulfur Iodine Lithium Chromium (III) 50 7/21/2015 HFinks '07 Oxidation States for Monatomic Ions 51 Atom Oxidation State Chlorine Cl- Sulfur S2- Iodine I- Lithium Li+ Chromium (III) Cr3+ 7/21/2015 HFinks '07 Oxidation States for Monatomic Ions Iron (III) Lead (II) Copper (II) 52 7/21/2015 HFinks '07 Oxidation States for Monatomic Ions 53 Iron (III) Fe3+ Lead (II) Pb2+ Copper (II) Cu2+ 7/21/2015 HFinks '07 Metallic Elements With Variable Oxidation Numbers 54 Transition metals, representative metals with p and d sublevels, and the inner transition metals typically have more than one oxidation state in compounds.. Electrons are lost in the following order: p,s,d 7/21/2015 HFinks '07 All Other Oxidation Numbers 55 Assigned so that the sum of the oxidation numbers of each element equals the net charge on the molecule or polyatomic ion. In neutral compounds, the sum of the positive and negative charge must equal 0. 7/21/2015 HFinks '07 Polyatomic Elements 56 These elements exist as neutral molecules in nature. Hydrogen, H2 Bromine, Br2 Nitrogen, N2 Iodine, I2 Oxygen, O2 Fluorine, F2 Chlorine, Cl2 Ozone, O3 Phosphorus, P4 Sulfur, S8 7/21/2015 HFinks '07 Naming Binary Compounds (Table in Packet) 57 Sodium & chlorine Magnesium & oxygen Lithium & fluorine Iron & sulfur Copper (II) & chlorine Lead (II) & chlorine Barium & oxygen Calcium & hydrogen 7/21/2015 HFinks '07 Naming Binary Compounds (Table in Packet) 58 NaCl MgO LiF FeS CuCl2 PbCl2 AlCl3 BaO CaH2 sodium chloride magnesium oxide lithium fluoride iron (II) sulfide copper (II) chloride iron (II) chloride aluminum chloride barium oxide calcium hydride 7/21/2015 HFinks '07 Examples of Metallic Elements with Variable Oxidation Numbers. 1st Ion Formed 2nd Ion Formed 3rd Ion Formed Vanadium [Ar]4s23d3 V 2+ V 3+ V 4+ & V 5+ Iron [Ar]4s23d6 Fe 2+ Fe 3+ Pb 2+ Pb 4+ Electron Element Lead 59 Configuration [Xe] 6s24f145d10 6p2 7/21/2015 HFinks '07 Isoelectronic? 60 These elements are not isoelectronic with a noble gas when the outermost electrons are lost. That is, they will not have the same number of electrons as the noble gas before it them in the periodic table. 7/21/2015 HFinks '07 EXPERIMENT: WATER OF HYDRATION 61 Purpose: Determine that all the water has been driven from a hydrate by heating a sample to constant mass. Use experimental data to calculate the moles of water released by a hydrate Infer the empirical formula of the hydrate from the formula of the anhydrous compound and experimental data. 7/21/2015 HFinks '07 Common Oxidation Numbers for Monatomic Ions 62 Na + = sodium Mg2+ = magnesium Ba2+ = barium K + = potassium Al3+ = aluminum Sr2+ = strontium Ca2+ = calcium 7/21/2015 Cl- = chloride S2- = sulfide O2- = oxygen F- = fluoride Br- = bromide I= iodide HFinks '07 Introduction 63 Many ionic compounds, when crystallized from an aqueous solution, will take up definite amounts of water as an integral part of their crystal structure. This water of crystallization may be driven off by heating the hydrated substance to convert it to its anhydrous form. 7/21/2015 HFinks '07 SAFETY 64 Handle the crucible and cover with clean crucible tongs only. Heat objects can be hot enough to burn even if they look cool. Always use crucible tongs to handle crucibles and covers. 7/21/2015 HFinks '07 Procedures 65 1. Mass the crucible and cover. Record 2. Add the magnesium sulfate to the crucible. 3. Mass the crucible, cover and magnesium sulfate. Record 4. Place the crucible and cover on the triangle as demonstrated. 5. Heat slowly for 3 min with the crucible partially covered. 6. Heat strongly for 10 min. 7. Remove crucible, cover and contents and let cool for 5 minutes. 8. Mass the crucible, cover and magnesium sulfate. 9. Heat strongly for 5 minutes. 10. Repeat #7 & 8. 7/21/2015 HFinks '07 CLEANUP & DISPOSAL 66 Clean all apparatus and your lab station. Return equipment to its proper place. Dispose of the magnesium sulfate in the sink. Flush with water. Wash your hands thoroughly after all work is finished and before you leave the lab. 7/21/2015 HFinks '07 DATA TABLE 67 1. Mass of empty crucible and cover 2. Mass of crucible, cover and magnesium sulfate hydrate 3. Mass of crucible, cover and anhydrous magnesium sulfate after 1st heating 4. Mass of crucible, cover and anhydrous magnesium sulfate after 2nd heating. 7/21/2015 HFinks '07 Fundamentals of Chemistry Homework: P. 114 – 115: 6 - 10 6. How many valence electrons are in an atom of each of the following elements? A) B) C) D) 68 Ne = 8 Br = 7 S=6 Sr = 2 E) F) G) H) 7/21/2015 Na = 1 As = 5 Sn = 4 In = 3 HFinks '07 FC : Question # 7 Classify each of the elements in question 6 as a metal, nonmetal, or metalloid. A) Ne = nonmetal B) Br = nonmetal C) S = nonmetal D) Sr = metal 69 7/21/2015 E) F) G) H) Na = metal As = metalloid Sn = metal In = metal HFinks '07 FC : Question # 8 Write the electron dot structure for each of the following elements. What is the group number of each element? A) Cl = 7A or 17 E) Kr = 8A or 18 B) Mg = 2A F) Cs = 1A C) C = 4 A or 14 G) O = 6A or 16 D) Bi = 6A or 15 H) P = 5A or 15 70 7/21/2015 HFinks '07 Lewis Structure Lewis structure is just the symbol of the element and the number of electrons on the outermost energy level. Example: sodium Na has one electron On its outermost energy level. Thus Na• 71 7/21/2015 HFinks '07 FC : Question # 9 The electron dot structures of four elements are shown. Without referring to the periodic table, give the family name for each element. A) B) C) D) 72 iodine = halogen barium = alkaline earth metal rubidium = alkali metal radon = noble gas 7/21/2015 HFinks '07 FC : Question # 10 73 a) Find the synthetic elements on the periodic table. b) What are the atomic numbers? c) Which synthetic elements are not found with the others on the periodic table? B) Elements that are 93 and higher are synthetic elements. C) Technetium (43) and promethium (61). 7/21/2015 HFinks '07 FC: Hwk.: P. 115 ( 11 – 15) List the elements along with their chemical symbols and atomic numbers that have names similar to the names of planets in the solar system. Mercury = Hg (80) Uranium = U (92) Neptunium = Np (93) Plutonium = Pu7/21/2015 (94) 74 HFinks '07 75 12. Rb – Atomic mass (86.1 u) K – density, 1.19 g/ml Cs – melting point, 290 K 7/21/2015 HFinks '07 76 13. Be and Sr F and I 7/21/2015 HFinks '07 77 14. Element hydrogen lithium nitrogen fluorine cobalt silver iodine mercury (a) (b) (c) 1,1 nm g 2,1 m s 2,15 nm g 2,17 nm g 4,9 m s 5,11 m s 5,17 nm s 6,12 m l 7/21/2015 (d) H(1 dot) Li (1 dot) N (5 dots) F (7 dots) I(7dots) HFinks '07 78 15. Americium is radioactive. 7/21/2015 HFinks '07 79 16. Electrical conductivity increases because the outer level electrons are farther from the nucleus and can move more freely 7/21/2015 HFinks '07 Naming Ternary Compounds Table in Packet 80 Iron (II) sulfite Copper (II) nitrate) Calcium permanganate Silver nitrate Potassium chlorate Magnesium carbonate Lead (II) hydroxide Nickel (II) phosphate Ammonium sulfite 7/21/2015 HFinks '07 81 17. Bromine and mercury are liquids. Mercury is a metal because it has two valence electrons that are not tightly held. Bromine is a nonmetal because it has seven valence electrons that are tightly held. 7/21/2015 HFinks '07 82 18. The noble gases are unreactive because they have a filled valence level. 7/21/2015 HFinks '07 83 19. As you move down a column, the atomic number increases and the wavelength of the mitted X ray decreases. 7/21/2015 HFinks '07 84 7/21/2015 HFinks '07 85 21. Ni and Zn are corrosion resistant, malleable, and relatively abundant. 7/21/2015 HFinks '07 Question For Today (Put in Cw/Hw Notebook) Ionic or Molecular Compounds? 86 1. 2. 3. 4. 5. 6. 7. sodium chloride NaCl barium oxide BaO carbon monoxide CO carbon dioxide CO2 calcium carbonate CaCO3 sulfur dioxide SO2 sodium nitrate NaNO3 7/21/2015 HFinks '07