1. IONIC AND COVALENT COMPOUNDS CHAPTERS 7, 8, 9 S

2. CHAPTER 7 AND 9 SEC. 7.1 – IONS SEC. 7.2 – IONIC BONDS AND IONIC COMPOUNDS SEC. 9.2 – NAMING AND WRITING FORMULAS FOR IONIC COMPOUNDS S

3. OBJECTIVES Understand how specific cations and anions form. Understand how ionic compounds form. Learn to name ionic compounds.

4. REVIEW CATIONS/ANIONS Cations Anions  atoms of metals  lose valence electrons  become positively charged  atoms of some nonmetals  gain electrons  become negatively charged

5. An ionic compound is a compound composed of cations and anions or a metal and a nonmetal. Although ionic compounds are composed of ions, they are electrically neutral. Anions and cations have opposite charges and attract one another by means of electrostatic forces. Ions and Ionic Bonding

6. The Octet Rule Octet rule - The electron configuration will replicate a noble gas and form an octet. Each atom will have eight valence e -

7. Group 1 metals have 1 valence electron, so they will lose 1 electron and produce cations with a charge of +1  Example: Li loses 1 valence electron to become Li +1

8. The Octet Rule - Cations Group 2 metals have 2 valence electrons, so they will lose 2 electrons and produce cations with a charge of +2  Example: Mg loses 2 valence electrons to become Mg +2

9. The figure at right lists the symbols of the cations formed by metals in Groups 1 and 2. Cations of Group 1 elements always have a charge of 1+. Cations of Group 2 elements always have a charge of 2+. Formation of Cations

10. Anions  atoms of some nonmetals  gain electrons  become negatively charged Electron configuration will follow octet rule Group 17 nonmetals have 7 valence electrons, so they will gain 1 electron and produce anions with a charge of -1  Example: F gains 1 valence electron to become F -1

11. Octet Rule – Anions Group 16 nonmetals have 6 valence electrons, so they will gain 2 electrons and produce anions with a charge of -2  Example: O gains 2 valence electrons to become O -2

12. Atoms of nonmetals and metalloids form anions by gaining enough valence electrons to attain an octet. Formation of Anions

14. The forces that hold anions and cations together in ionic compounds are called ionic bonds. The chemical formula of an ionic compound is known as a formula unit. o A formula unit is the lowest whole-number ratio of ions in an ionic compound Video – Forming ionic bonds Ionic Bonding

15. IONIC BONDING Na + Cl Rb + F

16. DO NOW Write the formula for the elements that combine by balancing out the charges. (Get a net charge of zero) Rb + Cl K + O

17. CHEMISTRY RIDDLES Q: Did you hear oxygen went on a date with potassium? A: It went OK. Q: What is the chemical formula for "coffee"? A: CoFe 2 Q: What is the chemical formula for "banana"? A: BaNa 2 Q: What is the show cesium and iodine love watching together? A: CSI Q: What did one ion say to the other? A: I've got my ion you. Q: What do you do with a sick chemist? A: If you can't helium, and you can't curium, then you might as well barium.

18. BINARY COMPOUNDS Binary compounds are made up of only 2 different elements o There can be more than 2 or more atoms though  NaCl  K 2 O  Al 2 S 3

19. To name a binary ionic compound:  Write the name of the cation first (always a metal)  Write the name of the anion, but change the ending to –ide  Note that any subscripts do not change the name NaCl sodium chlorine → chloride sodium chloride

20. TYPE I BINARY IONIC COMPOUNDS CHEMICAL NAMING K 2 O Al 2 S 3 Ca 3 P 2

21. WRITING FORMULAS FROM NAME When charges are not balanced, it is necessary to add subscripts o They represent the quantity of each element o No subscript equals 1 atom Li + 1 O 2- the charges are not equal o There is only one positive and two negatives o We need another positive charge to make them equal Li 2 O +1 -2

22. WRITING FORMULAS Sodium chloride  Radium arsenide  Aluminum selenide 

23. Polyatomic ions are ions that contain more than one atom o (SO 4 ) 2- o (OH) - o (PO 4 ) 3- o (NH 4 ) + It is important to note that the charge is distributed throughout all the atoms in the ion o Not only on the last atom

25. NAME THE FOLLOWING IONIC COMPOUNDS CONTAINING POLYATOMIC IONS Li 2 SO 4 NaNO 3 CaCO 3 MgSO 4 NH 4 Cl lithium sulfate sodium nitrate calcium carbonate magnesium sulfate ammonium chloride

27. NAMING IONIC COMPOUNDS CONTAINING TRANSITION METALS

28. PERIODIC CHART OF IONS

29. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 29 TYPE II BINARY IONIC COMPOUNDS Contain Metal Cation + Nonmetal Anion Transition metals can have multiple charges  For example iron can be either Fe 2+ or Fe 3+ Metal cation name is the metal name followed by a Roman Numeral in parentheses to indicate its charge  Determine charge on metal from anion charge first Nonmetal anion named by changing the ending on the nonmetal name to -ide

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31. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 31 WRITE THE NAME OF THE IONIC COMPOUND CONTAINING A TRANSITION METAL CuO Cu 2 O Fe 2 S 3 FeS PbCl 2 PbCl 4 Hg 2 Se copper (II) oxide copper (I) oxide iron (III) sulfide iron (II) sulfide lead (II) chloride lead (IV) chloride mercury (II) selenide Systematic Name

32. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 32 WRITE THE FORMULA FOR COMPOUNDS CONTAINING A TRANSITION METAL CoCl 3 CoCl 2 Fe 2 O 3 Cr 3 P 2 PbS Ti 2 Se 3 cobalt (III) chloride cobalt(II) chloride Iron (III) oxide Chromium (II) phosphide lead (II) sulfide Titanium (III) selenide

33. REVIEW Name the following compounds.Write Formulas. Type I 1.CaBr 2 7. Strontium phosphide 2.Li 2 O 8. Aluminum selenidePolyatomics 3. MgSO 4 9. Barium nitrate 4.(NH 4 ) 3 (PO 3 ) Type II 5. Fe 3 As 2 10. titanium ( III ) sulfide 6. CuBr

34. REVIEW Name the following compounds. Type I 1.CaBr 2 2.Li 2 O Polyatomics 3. MgSO 4 4.(NH 4 ) 3 (PO 3 ) Type II 5. Fe 3 As 2 6. CuBr KEY Calcium bromide Lithium oxide Magnesium sulfate Ammonium phosphite Iron( II ) arsenide Copper ( I ) bromide

35. REVIEW Write Formulas. Type I 7. Strontium phosphide 8. Aluminum selenide Polyatomics 9. Barium nitrate Type II 10. titanium ( III ) sulfide KEY Sr 3 P 2 Al 2 Se 3 Ba(NO 3 ) 2 Ti 2 S 3 +2 +3 -2 -3 +2 +3-2

36. CHAPTER 8 AND 9 COVALENT COMPOUNDS SEC. 8.1 – MOLECULAR COMPOUNDS SEC. 9.3 – NAMING AND WRITING FORMULAS FOR MOLECULAR COMPOUNDS

38. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. We learned that atoms can give up or accept electrons to form ions. These ions combine to form ionic compounds Previous Chapter

39. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. - Another way that atoms can combine is by sharing electrons. To form covalent compounds COVALENT (MOLECULAR) COMPOUNDS Sharing Electrons –Atoms that are held together by sharing electrons are joined by a covalent bond. –Two or more nonmetals form covalent compounds

40. COVALENT BONDING A molecule is a neutral group of atoms joined together by covalent bonds. Some molecules are made up of the same element Examples: O 2, F 2, Cl 2

41. What is an octet? An atom/element that has 8 valence electrons. What is the octet rule? An element will have 8 valence electrons around itself in a compound

42. PREDICTING COVALENT BONDS IN MOLECULAR COMPOUNDS USING MOLECULAR FORMULAS In covalent bonds, electron sharing usually occurs so that atoms attain the electron configurations of noble gases. The octet rule states that chemical compounds form so each atom will have 8 valence electrons  Exception: atoms trying to be like helium

43. We use Lewis Dot Diagrams to show covalent bonding

44. In the F 2 molecule, each fluorine atom contributes one electron to complete the octet. Two fluorine atoms share only one pair of valence electrons. That is a single covalent bond. *When we show the bonding, we use Lewis structures

45. A pair of valence electrons that is not shared between atoms is called an unshared pair, also known as a lone pair In F 2, each fluorine atom has three unshared pairs of electrons. Unshared pair of electrons

46. THE OCTET RULE IN COVALENT BONDING Hydrogen gas (H 2 ) atoms share only one pair of electrons, forming a single covalent bond. Single Covalent Bonds

47. FORMING MOLECULAR COMPOUNDS Hydrogen and chlorine

48. DO NOW Draw the Lewis dot diagram for the following compounds: CF 4 H 2 Se a.Ionic compound a.Covalent compound ______ 1. Shares electrons ______2. electrons are gained and lost

49. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 49 9.3 NAMING COVALENT COMPOUNDS -Contain only nonmetals -Known as covalent (molecular) compounds

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51. 51 NAMING COVALENT COMPOUNDS

52. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 52 EXAMPLES CO 2 CO BF 3 N 2 O 5 NO CCl 4 P 3 O 5 carbon dioxide carbon monoxide boron trifluoride dinitrogen pentoxide nitrogen monoxide carbon tetrachloride triphosphorus pentoxide

53. WRITE THE FORMULA Nitrogen dioxide Phosphorus trichloride Sulfur monoxide Dicarbon hexachloride Boron pentafluoride

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55. Most ionic compounds are crystalline solids at room temperature. The component ions in such crystals are arranged in repeating three-dimensional patterns. Properties of Ionic compounds

56. Water, which is a molecular compound, and sodium chloride, which is an ionic compound, are compared here. COMPARING MOLECULAR AND IONIC COMPOUNDS Collection of water molecules Molecule of water Chemical formulaH2OH2O Array of sodium ions and chloride ions Formula unit of sodium chloride Chemical formulaNaCl

57. 8.4 Polar Bonds and Molecules > 57 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. This table summarizes some of the characteristic differences between ionic and covalent (molecular) substances. Characteristics of Ionic and Molecular Compounds CharacteristicIonic CompoundMolecular Compound Bond formation Transfer of one or more electrons between atoms Sharing of electron parts between atoms Type of elementsMetallic and nonmetallicNonmetallic Physical stateSolidSolid, liquid, or gas Melting pointHigh (usually above 300°C)High (usually below 300°C) Solubility in waterUsually highHigh to low Electrical conductivity of aqueous solution Good conductorPoor to nonconducting Intermolecular Attractions and Molecular Properties Comparing Ionic compounds and Molecular Compounds