How to Use This Presentation

1. How to Use This Presentation • To View the presentation as a slideshow with effects select “View” on the menu bar and click on “Slide Show.” • To advance through the presentation, click the right-arrow key or the space bar. • From the resources slide, click on any resource to see a presentation for that resource. • From the Chapter menu screen click on any lesson to go directly to that lesson’s presentation. • You may exit the slide show at any time by pressing the Esc key.

2. Resources Bellringers Chapter Presentation Transparencies Standardized Test Prep Visual Concepts Math Skills

3. The Structure of Matter Chapter 5 Table of Contents Section 1 Compounds and Molecules Section 2 Ionic and Covalent Bonding Section 3 Compound Names and Formulas Section 4 Organic and Biochemical Compounds

4. Section 1 Compounds and Molecules Chapter 5 Objectives • Distinguishbetween compounds and mixtures. • Relate the chemical formula of a compound to the relative numbers of atoms or ions present in the compound. • Use models to visualize a compound’s chemical structure. • Describe how the chemical structure of a compound affects its properties.

5. Section 1 Compounds and Molecules Chapter 5 Bellringer Study the models of the water molecule, H2O, and the carbon dioxide molecule, CO2, and then answer the questions that follow. 1. Name some similarities between the molecules of H2O and CO2. 2. How are the molecules different?

6. Section 1 Compounds and Molecules Chapter 5 What Are Compounds? • Chemical bonds distinguish compounds from mixtures. • A compound is held together by chemical bonds. • A chemical bondis the attractive force that holds atoms or ions together. • A compound always has the same chemical formula.

7. Section 1 Compounds and Molecules Chapter 5 Compounds

8. Section 1 Compounds and Molecules Chapter 5 Chemical Bond

9. Section 1 Compounds and Molecules Chapter 5 What Are Compounds? continued • Chemical structure shows the bonding within a compound. • A chemical structure is the arrangement of atoms in a substance. • A bond length is the average distance between the nuclei of two bonded atoms. • A bond angle is the angle formed by two bonds to the same atom.

10. Section 1 Compounds and Molecules Chapter 5 Bond Length

11. Section 1 Compounds and Molecules Chapter 5 Bond Angle

12. Section 1 Compounds and Molecules Chapter 5 Models of Compounds • Some models give you an idea of bond lengths and angles. • The ball-and-stick model of watershown at right represents bondlengths and bond angles. • In structural formulas, only chemicalsymbols are used to representthe atoms. • Space-filling models show the spaceoccupied by atoms.

13. Section 1 Compounds and Molecules Chapter 5 How Does Structure Affect Properties? • Compounds with network structures are strong solids. • Example: Quartz is made of silicon and oxygen atoms bonded in a strong, rigid structure:

14. Section 1 Compounds and Molecules Chapter 5 How Does Structure Affect Properties? continued • Compounds made of networks of bonded ions have high melting points and boiling points. • Example: Table salt—sodium chloride—is made of a tightly packed repeating network of positive sodium ionsand negative chlorine ions.

15. Section 1 Compounds and Molecules Chapter 5 How Does Structure Affect Properties? continued • Some compounds are made of molecules. • Some compounds made of molecules are solids, others are liquids, others are gases. • The strength of attractions between molecules varies. • Attractions between water molecules are called hydrogen bonds. Hydrogen bonding is depicted on the next slide.

16. Section 1 Compounds and Molecules Chapter 5 Water Bonding

17. Section 2 Ionic and Covalent Bonding Chapter 5 Objectives • Explainwhy atoms sometimes join to form bonds. • Explain why some atoms transfer their valence electrons to form ionic bonds, while other atoms share valence electrons to form different bonds. • Differentiate between ionic, covalent, and metallic bonds. • Compare the properties of substances with different types of bonds.

18. Section 2 Ionic and Covalent Bonding Chapter 5 Bellringer You have already learned that atoms are the most stable when their outer energy levels are filled. One way to model atoms is using diagrams, such as the flowers shown below. To represent a stable atom, the flower diagram must have eight petals around the center. Assume that each petal represents an electron with a negative charge and that the centers of the flowers represent positively charged nuclei.

19. Section 2 Ionic and Covalent Bonding Chapter 5 Bellringer, continued 1. What had to happen to the flower diagrams so that they could represent stable atoms? 2. What happened to the charge on each of the flower diagrams? 3. What do you think will happen to the oppositely charged ions represented by the flower diagrams?

20. Section 2 Ionic and Covalent Bonding Chapter 5 What Holds Bonded Atoms Together? • Bonded atoms usually have a stable electron configuration. • Example: As shown at right,when two hydrogen atomsbond, their electron clouds overlap. The resulting hydrogenmolecule has an electronicstructure similar to the noblegas helium.

21. Section 2 Ionic and Covalent Bonding Chapter 5 What Holds Bonded Atoms Together? continued • Bonds can bend and stretch without breaking. • Although a “bar” is sometimes used to represent a bond between two atoms, chemical bonds behave more like flexible springs.

22. Section 2 Ionic and Covalent Bonding Chapter 5 Ionic Bonds • Ionic bonds are formed between oppositely charged ions. • As shown at right, ionic compounds are in the form of networks of formula units, not molecules. • When melted or dissolved in water, ionic compounds conduct electricity.

23. Section 2 Ionic and Covalent Bonding Chapter 5 Ionic Bonding

24. Section 2 Ionic and Covalent Bonding Chapter 5 Metallic Bonds • A metallic bond is a bond formed by the attraction between positively charged metal ions and the electrons around them. • Electrons move freely between metal atoms. • This model explains why metals: • conduct electricity • conduct heat • are flexible

25. Section 2 Ionic and Covalent Bonding Chapter 5 Metallic Bonding

26. Section 2 Ionic and Covalent Bonding Chapter 5 Covalent Bonds • A covalent bond is a bond formed when atoms share one or more pairs of electrons. • Covalent compounds can be solids, liquids, or gases. • Bonds in which atoms share electrons equally are called nonpolar covalent bonds,as shown below.

27. Section 2 Ionic and Covalent Bonding Chapter 5 Covalent Bonds, continued • Atoms do not always share electrons equally. • An unequal sharing of electrons forms a polar covalent bond. • Atoms may share more than one pair of electrons.

28. Section 2 Ionic and Covalent Bonding Chapter 5 Comparing Polar and Nonpolar Covalent Bonds

29. Section 2 Ionic and Covalent Bonding Chapter 5 Polyatomic Ions • A polyatomic ion is an ion made of two or more atoms. • There are many common polyatomic ions. Some are shown at right. • Parentheses group the atoms of a polyatomic ion. • Example: the chemical formula for ammonium sulfate is written as (NH4)2SO4, not N2H8SO4.

30. Section 2 Ionic and Covalent Bonding Chapter 5 Polyatomic Ions, continued • Some polyatomic anion names relate to their oxygen content. • An -ate ending is used to name an ion with more oxygen. • Examples: sulfate (SO42–), nitrate (NO3–), chlorate (ClO3–) • An -ite ending is used to name an ion with less oxygen. • Examples: sulfite (SO32–), nitrite (NO2–), chlorite (ClO2–)

31. Section 2 Ionic and Covalent Bonding Chapter 5 Comparing Ionic and Molecular Compounds

32. Section 3 Compound Names and Formulas Chapter 5 Objectives • Namesimple ionic and covalent compounds. • Predict the charge of a transition metal cation in an ionic compound. • Write chemical formulas for simple ionic compounds. • Distinguish a covalent compound’s empirical formula from its molecular formula.

33. Section 3 Compound Names and Formulas Chapter 5 Bellringer Below are models of two imaginary molecules made with construction toys. In the first model, the sticks and balls are simply pushed together. In the second model, in the shaded connection, some clay has been stuck into the holes to hold the sticks more tightly. In a similar way, not all bonds between atoms are the same. Some are tighter than others.

34. Section 3 Compound Names and Formulas Chapter 5 Bellringer, continued 1. If the first molecule were stressed, where might it break apart? 2. Where would the second model most likely break apart? Why? 3. What would you need more of to pull the shaded balls apart, when compared to the first model?

35. Section 3 Compound Names and Formulas Chapter 5 Reading Chemical Formulas

36. Section 3 Compound Names and Formulas Chapter 5 Naming Ionic Compounds • Names of cations include the elements of which they are composed. • Example: when an atom of sodium loses an electron, a sodium ion, Na+, forms. • Names of anions are altered names of elements. • Example: when an atom of fluorine gains an electron, a fluoride ion, F–, forms.

37. Section 3 Compound Names and Formulas Chapter 5 Naming Ionic Compounds, continued • Some cation names must show their charge. • Iron can form two different cations. Fe2O3 is made of Fe3+ ions, so it is named iron(III)oxide. FeO is made of Fe2+ ions, so it is named iron(II) oxide. • To determine the charge of a transition metal cation, look at the total charge of the compound. • You can tell that the iron ion in Fe2O3 has a charge of 3+ because the total charge of the compound must be zero, and an oxide ion, O2–, has a a charge of 2–. • Fe2O3→ (2× 3+) + (3×2–) = 0

38. Section 3 Compound Names and Formulas Chapter 5 Naming Ionic Compounds

39. Section 3 Compound Names and Formulas Chapter 5 Math Skills Writing Ionic Formulas What is the chemical formula for aluminum fluoride? 1. List the symbols for each ion. Symbol for an aluminum ion (from Table 4 in your book): Al3+Symbol for a fluoride ion from (from Table 5 in your book): F– 2. Write the symbols for the ions with the cation first. Al3+ F–

40. Section 3 Compound Names and Formulas Chapter 5 Math Skills, continued 3. Find the least common multiple of the ions’ charges. The least common multiple of 3 and 1 is 3. To make a neutral compound, you need a total of three positive charges and three negative charges. To get three positive charges: you need only one Al3+ ion because 1 × 3+ = 3+. To get three negative charges: you need three F– ions because 3 × 1– = 3– 4. Write the chemical formula, indicating with subscripts how many of each ion are needed to make a neutral compound. • AlF3

41. Section 3 Compound Names and Formulas Chapter 5 Naming Covalent Compounds • Numerical prefixes, shown in Table 7 in your book, are used to name covalent compounds of two elements. • Examples: There are one boron atom and three fluorine atoms in boron trifluoride, BF3. Dinitrogen tetroxide, N2O4, is made of two nitrogen atoms and four oxygen atoms.

42. Section 3 Compound Names and Formulas Chapter 5 Naming Covalently-Bonded Compounds

43. Section 3 Compound Names and Formulas Chapter 5 Naming Compounds Using Numerical Prefixes

44. Section 3 Compound Names and Formulas Chapter 5 Chemical Formulas for Covalent Compounds • A compound’s simplest formula is its empirical formula. • An empirical formula tells the composition of a compound in terms of the relative numbers and kinds of atoms in the simplest ratio. • Empirical formulas are determined by taking the ratio of masses of elements within a compound and multiplying them by molar masses, as shown at right.

45. Section 3 Compound Names and Formulas Chapter 5 Chemical Formulas for Covalent Compounds, continued • Different compounds can have the same empirical formula. • Molecular formulas are determined from empirical formulas. • A molecular formula is a chemical formula that shows the number and kinds of atoms in a molecule. • In some cases, a compound’s molecular formula is the same as its empirical formula.

46. Section 3 Compound Names and Formulas Chapter 5 Comparing Molecular and Empirical Formulas

47. Section 4 Organic and Biochemical Compounds Chapter 5 Objectives • Describehow carbon atoms bond covalently to form organic compounds. • Identify the names and structures of groups of simple organic compounds and polymers. • Identify what makes up the polymers that are essential to life.

48. Section 4 Organic and Biochemical Compounds Chapter 5 Bellringer Below are drawings of several different things. Study them, and consider what elements they contain. Then answer the questions that follow.

49. Section 4 Organic and Biochemical Compounds Chapter 5 Bellringer, continued 1. Which of the itemscontain carbon? 2. What is the maindifference between theseitems and the others? 3. Would carbon be morelikely to form covalentor ionic bonds?

50. Section 4 Organic and Biochemical Compounds Chapter 5 Organic Compounds • In chemistry, the word organic is used to describe certain compounds. • An organic compound is a covalently bonded compound that contains carbon, excluding carbonates and oxides. • Many ingredients of familiar substances contain carbon.