CHAPTER 7 CHEMICAL FORMULAS AND BONDING

Transcription

1 Name Date Period CHAPTER 7 CHEMICAL FORMULAS AND BONDING IONIC COMPOUNDS 1. What are the two types of bonds that will be discussed in this chapter? 2. How do ionic bonds form? 3. What do you call the positive ions? What do you call the negatives? 4. Quickly list a few properties of ionic compounds. 5. We covered the octet rule in the last chapter, in your own words restate the octet rule. 6. Besides cations and anions, there are 2 general types of ions listed in the book, list them and define them. a. b. 7. What are the transition metals? 8. What are the post-transition metals? 9. Why do transition and post-transition metals have roman numerals after their names? 10. In a chemical name how would you distinguish a Cu + from a Cu +2? 11. In this chapter you will not have to memorize the names and charges of any polyatomic ions (except hydroxide), where can you find the names and charges of most of them? What is hydroxide? 12. Looking at the chart on page 232, when fluorine becomes its most common ion (F - ) is no longer called fluorine it is now called fluor. Therefore, when atoms become anions, you drop the off the end and add. 13. What is a binary ionic compound? 14. How do you name binary ionic compounds? 15. All ionic compounds are electrically. 16. How can the question above be true when ionic compounds consist completely of charged particles? 17. What is the criss-cross method of writing chemical formulas? 18. Use the criss-cross method of writing formulas for aluminum +3 ions and oxygen -2 ions. Last Updated: 12/6/11 Page 1/11

2 19. Try the criss-cross method on sodium +1 ions and sulfur -2 ions. 20. Try the criss-cross method on calcium +2 and phosphorous Use the Preiodic Table to determine charges and then find the formula of the compound of lithium and nitrogen. 22. Find the formula of the compound of barium and selenium. 23. Find the formula of the compound of aluminum and bromine. 24. Find the formula of the compound of magnesium and chlorine. 25. Find the formula of the compound of iron forming a +2 ion and fluorine. 26. Find the formula of the compound of titanium forming a +4 ion and nitrogen. 27. Find the formula of the compound of nickel forming a +3 ion and chlorine. 28. Find the formula of the compound of sodium and nitrate (NO 3 - ). 29. Find the formula of the compound of calcium and sulfate (SO 4 2- ). 30. Find the formula of the compound of aluminum and carbonate (CO 3 2- ). 31. Find the formula of the compound of ammonium (NH 4 +) and chlorate (ClO 3 - ). 32. Find the formula of the compound of copper forming a +2 ion and and chlorate (ClO 3 - ). 33. Find the formula of the compound of lithium and nitrate (NO 3 - ). 34. Find the formula of the compound of magnesium and phosphate (PO 4 3- ). a. Why does the phosphate compound need parentheses and the nitrate compound doesn t? b. How many of each atom are there in the correct chemical formula of the compound formed? 35. What number is not included in chemical formulas? 36. How should Mg 2 O 2 be written? Why? 37. What is the definition of a hydrate? 38. What is the name of something opposite of a hydrate? Last Updated: 12/6/11 Page 2/11

3 Jill was handed an assortment of index cards. Each index card had the chemical symbol for an ion written on it, as shown below. 39. Jill formed ionic compounds using the index cards. She combined sodium and zinc to form the compound Na 2 Zn. Is this a possible ionic compound? Why or why not? 40. Jill then wrote the formulas for all the possible compounds that sodium could form with the other ions. What formulas did she write? 41. Which monatomic ions in the cards to the right underwent oxidation to become the ions listed on the cards? Which ones underwent reduction? 42. Jill also wrote formulas for the ionic compounds listed below. Identify whether each formula is correct or incorrect. If the formula is incorrect, change it to make it correct. a. ZnCl 3 b. Al 3 O 2 c. Ca 3 (PO 4 ) 2 PO 4-3 Zn +2 Al +3 Na + Ni +2 Cl - O -2 OXIDATION/REDUCTION (FROM ANOTHER CHAPTER) Oxidation Losing Is Electrons = Loss (of e - ) Oxidation says Reduction Gaining Is Electrons = Gain (of e - ) Reduction 43. To make salt (sodium chloride), we can take sodium metal (or a bunch of sodium atoms) and react them with a bunch of chlorine molecules (chorine gas is 2 chlorine atoms stuck together, Cl 2 ). Try to write the reaction for what is happening. 44. What is the difference between the sodium atoms on the left side of the equation versus the sodium atoms on the right side in terms of charge? What s the difference between the chlorines? 45. If atoms lose electrons we say they are oxidized, if atoms gain electrons, they are reduced. So based on your answer to the question above, did sodium undergo oxidation or reduction. What happened to chlorine? 46. When your car rusts, the steel (which is mostly iron) reacts with oxygen from the air to form iron (III) oxide. Write the chemical equation for this. 47. Which element from the above reaction was oxidized? Which one underwent reduction? Last Updated: 12/6/11 Page 3/11

4 COVALENT COMPOUNDS 48. In an ionic bond electrons are. 49. In a covalent bond electrons are. 50. A group of atoms is stuck together by a covalent bond is called a. 51. To describe the composition of a molecular compound, chemists often use a formula. 52. How does the above formula differ from an empirical formula? 53. Explain how the octet rule helps explain why covalent bonds occur. 54. Explain why ionic compounds are solids at room temperature, while covalent compounds are often gases or liquids? 55. Why are covalently bonded molecular compounds never conductve? 56. Study the flowcharts on the back of this page; ask the teacher any questions on any of the meanings. COVALENT VS. IONIC COMPOUNDS 57. You are on the planet Pluto and fall into a pool of liquid. Is the liquid probably an ionic or covalently bonded compound? EXPLAIN. 58. You are on the planet Mercury and find a solid hunk of rock. You try to melt it with a blow torch, but it won t melt. Is it probably Co(NO 3 ) 3 or C 2 N 4 O 3? EXPLAIN. 59. Contrast the typical physical states of ionic and covalent substances. Explain why they differ. 60. You are swimming in a covalently bonded liquid substance. Lightning strikes the liquid and you get electrocuted. What must be true about that liquid? 61. Your friend says they are chewing a new ionically bonded chewing gum. What is wrong with that statement? 62. Could wires be insulated with ionic compounds? Why would that be a problem if it got wet? Last Updated: 12/6/11 Page 4/11

5 NAME THESE COMPOUNDS THAT CONTAIN TRANSITION METALS (D-BLOCK METALS) 63. CuO 3 rd Therefore the total charge from the cations must be 2 nd determine the Resulting charge from all the anions 4 th divide the total charge by the number of cations 1 st Determine the Charge on the individual anion Cu O Cation Anion Name 64. Cu 2 O 3 rd Therefore the total charge from the cations must be 2 nd determine the Resulting charge from all the anions 4 th divide the total charge by the number of cations 1 st Determine the Charge on the individual anion Cu 2 O Cation Anion Name 65. Cu 2 O 3 3 rd Therefore the total charge from the cations must be 2 nd determine the Resulting charge from all the anions 4 th divide the total charge by the number ofcations 1 st Determine the Charge on the individual anions Cu 2 O Cation Anion 3 Name 66. MnO 2 3 rd Therefore the total charge from the cations must be 2 nd determine the Resulting charge from all the anions 4 th divide the total charge by the number of cations 1 st Determine the Charge on the individual anions Mn O 2 Cation Anion Name Last Updated: 12/6/11 Page 5/11

6 7-1 IONIC BONDING (WRITE THE CORRECT FORMULA FOR EACH OF THE FOLLOWING IONIC COMPOUNDS LISTED BELOW.) Compound Name Formula Compound Name Formula 67. lithium nitride 68. nickel(ii) nitride (Roman numeral indicates the charge on the element) 69. lithium nitrite 70. Nickel(II) nitrite 71. lithium nitrate 72. nickel(ii) nitrate 73. ammonium chloride (the only positive polyatomic ion) 74. zinc(ii) chloride 75. magnesium chlorite 76. barium chloride 77. magnesium chlorate 78. silver(i) bromate 79. magnesium hydroxide (one of 2 polyatomic ions that end in ide) 80. gold(iii) bromide 81. iron(iii) sulfite 82. lithium bromide 83. iron(iii) sulfate 84. potassium iodide 85. chromium(iii) sulfide 86. copper(ii) iodide 87. magnesium phosphate 88. potassium Iodate magnesium hydrogen phosphate hydrogen phosphate is on the back of the PT magnesium dihydrogen phosphate dihydrogen phosphate is on the back of the PT 90. ammonium carbonate 92. lithium acetate 93. Sodium bisulfate 94. strontium thiocyanate 95. calcium bicarbonate 96. tin(iv) oxide 97. sodium acetate 98. hydrogen cyanide (one of 2 polyatomic ions that end in ide) 99. cobalt(ii) fluoride 100. sodium hypochlorite 101. sodium phosphide 102. calcium chromate 103. potassium permanganate 104. osmium (III) dichromate 105. copper(ii) sulfate pentahydrate (penta = 5, hydrate = H 2O) CuSO 4 5H 2 O 106. barium hydroxide octahydrate 107. Nickel (II) chloride hexahydrate 108. Last Updated: 12/6/11 Page 6/11

7 7 3 WRITE THE NAMES &/OR FORMULAS FOR EACH OF THE FOLLOWING Ionic Compound Name Formula Compound Name Formula 109. FeCl 110. CaS 111. FeCl CaSO FeCl CaSO Fe 2 O 116. NaClO 117. FeO 118. Na 2 CO 3 H 2 O 119. Fe 2 O CuSO 4 5 H 2 O 121. FeO Na 2 CO KOH 124. BaF LiI 126. Cu(NO 3 ) AlF AgI 129. Iron(II) chloride 130. Nickel(II) sulfate 131. Magnesium oxide 132. Zinc(II) phosphate 133. Cobalt(II) nitrate 134. Sodium nitride 135. Magnesium sulfate 136. Copper(I) carbonate 137. Ammonium chloride 138. Ammonium sulfate 139. Chromium(III) phosphate 140. Sodium Hypochlorite 141. Barium hydroxide 142. Magnesium sulfate heptahydrate 143. Lead(II) sulfide 144. Calcium sulfate dihydrate Covalently Bonded Molecular Compounds 145. CO 146. ClO CO P 4 S C 2 O 150. NO 151. C 2 O SF SiO XeF PCl SbF Silicon tetrafluoride 158. Nitrogen trihydride (ammonia) 159. Dinitrogen monoxide 160. Sulfur dioxide 161. Sulfur trioxide 162. Dihydrogen monoxide (water) 163. Dinitrogen pentoxide 164. Carbon disulfide 165. Iodine pentafluoride 166. Carbon tetraiodide 167. Sulfur hexafluoride 168. Boron trichloride Last Updated: 12/6/11 Page 7/11

8 Fill in the following table of mixed IONIC and COVALENT compounds. Compound Name Formula Compound Name Formula 169. Co 2 O Mercury(I) chloride 171. KMnO Sodium hydride 173. Calcium sulfide 174. K 2 SO Cl 2 O Lithium sulfate 177. Copper(I) oxide 178. Nitrogen trichloride 179. Rb 2 O 180. Sodium hydroxide 181. Phosphorous trichloride 182. SnF BaSO Lead (IV) oxide 185. NH 4 NO Silver(I) cyanide 187. Ru(NO 3 ) (NH 4 )(HSO 4 ) 189. Cesium bromide 190. Cobalt(II) perchlorate 191. Chlorine trifluoride 192. ClO Chromium (III) carbonate 194. Dihydrogen monoxide Last Updated: 12/6/11 Page 8/11

9 DETERMINING THE # OF ATOMS For the following indicate the # of atoms represented molecule of magnesium hydroxide Mg O H molecules of magnesium hydroxide molecule of aluminum sulfate molecules of aluminum sulfate molecule of dinitrogen tetraoxide molecules of dinitrogen tetraoxide Mg O H Al S O Al S O N N O S 201. Al 2 O Al 2 O 3 Al Al O O 203. CaCO CaCO Al 2 (CO 3 ) Al 2 (CO 3 ) C 2 H 4 O C 2 H 4 O 2 Ca C O Ca C O Al C O Al C O C H O C H O Last Updated: 12/6/11 Page 9/11

10 DETERMINING NAMES FROM FORMULAS DETERMINE BOND TYPE - If metal or ammonium present, then ionic - Otherwise, Covalent IONIC: Is the cation a transition or post-transition metal? COVALENT: Is there more than 1 of the 1 st element? YES: Determine the charge by charge balance from the anion, then write the name followed by roman numerals indicating the charge. NO: Write the name of the element or ammonium. YES: Determine the prefix & write the name of the element. NO: Just write the name of the element. Is it bound to a single atom or polyatomic ion? Write the root of the 2 nd followed by ide & any necessary prefixes. SINGLE ATOM: Use the root & add ide to the end. POLYATOMIC: Write the full name of the polyatomic ion. NUMERICAL PREFIXES 1 mono- 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca- For practice, go to & click on Nomenclature, & then on (161) Names to Formulas or on (160) Formulas to Names or click on Stoichiometry, & then on (130) Balancing Equations Last Updated: 12/6/11 Page 10/11

11 DETERMINING FORMULAS FROM NAMES Determine Bond Type - If a metal or ammonium present, then ionic - - Otherwise, covalent - YES, TRANSITION OR POST-TRANSITION: Write the symbol from the Per. Table & the charge from the name (roman numeral in parenthesis). IONIC: Is the cation a transition or post-transition metal? NO, AMMONIUM: Write NH 4 +. Is the anion a single type of non-metallic element (ends in ide except for hydroxide & cyanide) or a polyatomic ion (ends in ate or ite)? NO: Elements, Write the element symbol & charge obtained from the Per Table. COVALENT: Find the non-metallic elements symbols from the periodic table. Note the 2 nd elements name will have been modified with ide at the end. Write the formula using the symbols and appropriate subscripts based on the prefixes from the name. NOTE no prefix means 1 of that element. SINGLE ELEMENT: Write down the element symbol & its ionic charge from the periodic. POLYATOMIC: Remember or look up the formula & charge for the polyatomic ion and write it down. Do the charges cancel each other out? YES: Just erase all the charges and leave the elements written the way they are NO: Use charge balance (criss-cross rule) to determine the quantities of cations & anions present in the formula. Reduce as necessary. If >1 polyatomic ion required, put parenthesis around the polyatomic ion formula & charge, and put the subscript outside the parenthesis. NUMERICAL PREFIXES 1 mono- 2 di- 3 tri- 4 tetra- 5 penta- 6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca- Last Updated: 12/6/11 Page 11/11