1. Chapter 7: Ionic Compounds and Metals. CHEMISTRY Matter and Change

2. Section 7.1Ion FormationIon Formation Section 7.2Ionic Bonds and Ionic CompoundsIonic Bonds and Ionic Compounds Section 7.3Names and Formulas for Ionic CompoundsNames and Formulas for Ionic Compounds Section 7.4Metallic Bonds and the Properties of MetalsMetallic Bonds and the Properties of Metals Exit Click a hyperlink to view the corresponding slides. Table Of Contents CHAPTER 7

3. Define a chemical bond. octet rule: atoms tend to gain, lose, or share electrons in order to acquire eight valence electrons chemical bond cation anion Describe the formation of positive and negative ions. Relate ion formation to electron configuration. Ions are formed when atoms gain or lose valence electrons to achieve a stable octet electron configuration. Ion Formation SECTION 7.1

4. Valence Electrons and Chemical Bonds A chemical bond * Chemical bonds form by the attraction between the positive nucleus of one atom and the negative electrons of another atom. Ion Formation SECTION 7.1

5. Valence Electrons and Chemical Bonds (cont.) Atom’s try to form the octet—the stable arrangement of eight valence electrons in the outer energy level—by gaining or losing valence electrons. Ion Formation SECTION 7.1

6. Positive Ion Formation * is called a cation. This figure illustrates how sodium loses one valence electron to become a sodium cation. Ion Formation SECTION 7.1

7. Positive Ion Formation (cont.) Metals are reactive because they lose valence electrons easily. Ion Formation SECTION 7.1

8. Positive Ion Formation (cont.) Transition metals commonly form 2+ or 3+ ions, but can form greater than 3+ ions. Other relatively stable electron arrangements are referred to as pseudo-noble gas configurations. Ion Formation SECTION 7.1

9. Negative Ion Formation An anion is a negatively charged ion. The figure shown here illustrates chlorine gaining an electron to become a chlorine ion. Ion Formation SECTION 7.1

10. Negative Ion Formation (cont.) Nonmetal ions gain the number of electrons required to fill an octet. Some nonmetals can gain or lose electrons to complete an octet. Ion Formation SECTION 7.1

11. Describe the formation of ionic bonds and the structure of ionic compounds. compound: a chemical combination of two or more different elements Generalize about the strength of ionic bonds based on the physical properties of ionic compounds. Categorize ionic bond formation as exothermic or endothermic. SECTION 7.2 Ionic Bonds and Ionic Compounds

12. ionic bond ionic compound crystal lattice electrolyte lattice energy Oppositely charged ions attract each other, forming electrically neutral ionic compounds. SECTION 7.2 Ionic Bonds and Ionic Compounds

13. Formation of an Ionic Bond * is called an ionic bond. * are called ionic compounds. Binary ionic compounds contain only two different elements—a metallic cation and a nonmetallic anion. SECTION 7.2 Ionic Bonds and Ionic Compounds

14. Formation of an Ionic Bond (cont.) SECTION 7.2 Ionic Bonds and Ionic Compounds

15. Properties of Ionic Compounds Positive and negative ions exist in a ratio determined by the number of electrons transferred from the metal atom to the non-metal atom. The repeating pattern of particle packing in an ionic compound is called an ionic crystal. SECTION 7.2 Ionic Bonds and Ionic Compounds

16. Properties of Ionic Compounds (cont.) The strong attractions among the positive and negative ions result in the formation of the crystal lattice. A crystal lattice is the *. SECTION 7.2 Ionic Bonds and Ionic Compounds

17. Properties of Ionic Compounds (cont.) Melting point, boiling point, and hardness depend on the strength of the attraction. SECTION 7.2 Ionic Bonds and Ionic Compounds

18. In a solid, ions are locked into position and electrons cannot flow freely—solid ions are poor conductors of electricity. Liquid ions or ions in aqueous solution have electrons that are free to move, so they conduct electricity easily. * is an electrolyte. SECTION 7.2 Ionic Bonds and Ionic Compounds Properties of Ionic Compounds (cont.)

19. This figure demonstrates how and why crystals break when an external force is applied. SECTION 7.2 Ionic Bonds and Ionic Compounds

20. Energy and the Ionic Bond Reactions that absorb energy are endothermic. Reactions that release energy are exothermic. SECTION 7.2 Ionic Bonds and Ionic Compounds

21. Energy and the Ionic Bond (cont.) * is referred to as the lattice energy. Lattice energy is directly related to the size of the ions that are bonded. SECTION 7.2 Ionic Bonds and Ionic Compounds

22. Energy and the Ionic Bond (cont.) Smaller ions form compounds with more closely spaced ionic charges, and require more energy to separate. Electrostatic force of attraction is inversely related to the distance between the opposite charges. The smaller the ion, the greater the attraction. SECTION 7.2 Ionic Bonds and Ionic Compounds

23. Energy and the Ionic Bond (cont.) The value of lattice energy is also affected by the charge of the ion. SECTION 7.2 Ionic Bonds and Ionic Compounds

24. Relate a formula unit of an ionic compound to its composition. nonmetal: an element that is generally a gas or a dull, brittle solid and is a poor conductor of heat and electricity Write formulas for ionic compounds and oxyanions. Apply naming conventions to ionic compounds and oxyanions. SECTION 7.3 Names and Formulas for Ionic Compounds

25. formula unit monatomic ion oxidation number polyatomic ion oxyanion In written names and formulas for ionic compounds, the cation appears first, followed by the anion. SECTION 7.3 Names and Formulas for Ionic Compounds

26. Formulas for Ionic Compounds When writing names and formulas for ionic compounds, the cation appears first followed by the anion. Chemists around the world need to communicate with one another, so a standardized system of naming compounds was developed. SECTION 7.3 Names and Formulas for Ionic Compounds

27. Formulas for Ionic Compounds (cont.) A formula unit * Monatomic ions are *. SECTION 7.3 Names and Formulas for Ionic Compounds

28. Formulas for Ionic Compounds (cont.) Oxidation number, or oxidation state, is * SECTION 7.3 Names and Formulas for Ionic Compounds

29. The symbol for the cation is always written first, followed by the symbol of the anion. Subscripts represent the number of ions of each element in an ionic compound. The total charge must equal zero in an ionic compound. Formulas for Ionic Compounds (cont.) SECTION 7.3 Names and Formulas for Ionic Compounds

30. Formulas for Ionic Compounds (cont.) Polyatomic ions are * Since polyatomic ions exist as a unit, never change subscripts of the atoms within the ion. If more than one polyatomic ion is needed, place parentheses around the ion and write the appropriate subscript outside the parentheses. SECTION 7.3 Names and Formulas for Ionic Compounds

31. SECTION 7.3 Names and Formulas for Ionic Compounds Formulas for Ionic Compounds (cont.)

32. Names for Ions and Ionic Compounds An oxyanion is a *. SECTION 7.3 Names and Formulas for Ionic Compounds

33. Names for Ions and Ionic Compounds (Cont.) SECTION 7.3 Names and Formulas for Ionic Compounds

34. Chemical nomenclature is a systematic way of naming compounds. –Name the cation followed by the anion. –For monatomic cations use the element name. –For monatomic anions, use the root element name and the suffix –ide. –To distinguish between different oxidation states of the same element, the oxidation state is written in parentheses after the name of the cation. –When the compound contains a polyatomic ion, name the cation followed by the name of the polyatomic ion. Names for Ions and Ionic Compounds (Cont.) SECTION 7.3 Names and Formulas for Ionic Compounds

35. SECTION 7.3 Names and Formulas for Ionic Compounds Names for Ions and Ionic Compounds (Cont.)

36. Describe a metallic bond. physical property: a characteristic of matter that can be observed or measured without altering the sample’s composition Relate the electron sea model to the physical properties of metals. Define alloys, and categorize them into two basic types. SECTION 7.4 Metallic Bonds and the Properties of Metals

37. electron sea model delocalized electron metallic bond alloy Metals form crystal lattices and can be modeled as cations surrounded by a “sea” of freely moving valence electrons. SECTION 7.4 Metallic Bonds and the Properties of Metals

38. Metals are not ionic but share several properties with ionic compounds. Metals also form lattices in the solid state, where 8 to 12 other atoms closely surround each metal atom. SECTION 7.4 Metallic Bonds and the Properties of Metals

39. Within the crowded lattice, the outer energy levels of metal atoms overlap. The electron sea model proposes that all metal atoms in a metallic solid *. *and are referred to as delocalized electrons, forming a metallic cation. SECTION 7.4 Metallic Bonds and the Properties of Metals Metallic Bonds and the Properties of Metals (Cont.)

40. A metallic bond is the * SECTION 7.4 Metallic Bonds and the Properties of Metals Metallic Bonds and the Properties of Metals (Cont.)

41. Boiling points are much higher than melting points because of the energy required to separate atoms from the groups of cations and electrons. SECTION 7.4 Metallic Bonds and the Properties of Metals Metallic Bonds and the Properties of Metals (Cont.)

42. Metals are malleable because they can be hammered into sheets. Metals are ductile because they can be drawn into wires. SECTION 7.4 Metallic Bonds and the Properties of Metals Metallic Bonds and the Properties of Metals (Cont.)

43. Mobile electrons surrounding positively charged nuclei make metals good conductors of electricity and heat. As the number of delocalized electrons increases, so does hardness and strength. SECTION 7.4 Metallic Bonds and the Properties of Metals Metallic Bonds and the Properties of Metals (Cont.)

44. Metal Alloys An alloy is a *. –Ex. Stainless steel, brass, cast iron The properties of alloys differ from the elements they contain. –Ex. Steel is iron mixed with at least one other element. Some properties of iron are present, like magnetism, but steel is stronger than iron. SECTION 7.4 Metallic Bonds and the Properties of Metals

45. Metal Alloys (cont.) SECTION 7.4 Metallic Bonds and the Properties of Metals

46. Substitutional alloys are formed when some atoms in the original metallic solid are replaced by other metals of similar atomic structure. Interstitial alloys are formed when small holes in a metallic crystal are filled with smaller atoms. SECTION 7.4 Metallic Bonds and the Properties of Metals Metal Alloys (cont.)

47. Key Concepts A chemical bond is the force that holds two atoms together. Some atoms form ions to gain stability. This stable configuration involves a complete outer energy level, usually consisting of eight valence electrons. Ions are formed by the loss or gain of valence electrons. The number of protons remains unchanged during ion formation. SECTION 7.1 Ion Formation Study Guide

48. Ionic compounds contain ionic bonds formed by the attraction of oppositely charged ions. Ions in an ionic compound are arranged in a repeating pattern known as a crystal lattice. Ionic compound properties are related to ionic bond strength. Ionic compounds are electrolytes; they conduct an electric current in the liquid phase and in aqueous solution. SECTION 7.2 Ionic Bonds and Ionic Compounds Study Guide Key Concepts

49. Lattice energy is the energy needed to remove 1 mol of ions from its crystal lattice. SECTION 7.2 Ionic Bonds and Ionic Compounds Study Guide

50. Key Concepts A formula unit gives the ratio of cations to anions in the ionic compound. A monatomic ion is formed from one atom. The charge of a monatomic ion is its oxidation number. Roman numerals indicate the oxidation number of cations having multiple possible oxidation states. Polyatomic ions consist of more than one atom and act as a single unit. SECTION 7.3 Names and Formulas for Ionic Compounds Study Guide

51. Key Concepts To indicate more than one polyatomic ion in a chemical formula, place parentheses around the polyatomic ion and use a subscript. Study Guide SECTION 7.3 Names and Formulas for Ionic Compounds

52. Key Concepts A metallic bond forms when metal cations attract freely moving, delocalized valence electrons. In the electron sea model, electrons move through the metallic crystal and are not held by any particular atom. The electron sea model explains the physical properties of metallic solids. Metal alloys are formed when a metal is mixed with one or more other elements. Study Guide SECTION 7.3 Metallic Bonds and the Properties of Metals