Understanding Ionic Compounds and Metals Formation

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

2. Table Of Contents CHAPTER7 Section 7.1 Ion Formation Section 7.2 Ionic Bonds and Ionic Compounds Section 7.3 Names and Formulas for Ionic Compounds Section 7.4 Metallic Bonds and the Properties of Metals Click a hyperlink to view the corresponding slides. Exit

3. Ion Formation SECTION7.1 • Define a chemical bond. octet rule: atoms tend to gain, lose, or share electrons in order to acquire eight valence electrons • Describe the formation of positive and negative ions. • Relate ion formation to electron configuration. chemical bond cation anion Ions are formed when atoms gain or lose valence electrons to achieve a stable octet electron configuration.

4. Ion Formation SECTION7.1 Valence Electrons and Chemical Bonds • A chemical bond is the force that holds two atoms together. • Chemical bonds form by the attraction between the positive nucleus of one atom and the negative electrons of another atom.

5. Ion Formation SECTION7.1 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.

6. Ion Formation SECTION7.1 Positive Ion Formation • A positively charged ion is called a cation. • This figure illustrates how sodium loses one valence electron to become a sodium cation.

7. Ion Formation SECTION7.1 Positive Ion Formation(cont.) • Metals are reactive because they lose valence electrons easily.

8. Ion Formation SECTION7.1 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.

9. Ion Formation SECTION7.1 Negative Ion Formation • An anionis a negatively charged ion. • The figure shown here illustrates chlorine gaining an electron to become a chlorine ion.

10. Ion Formation SECTION7.1 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.

11. Section Check SECTION7.1 Oxygen gains two electrons to form what kind of ion? A.1– anion B.2– anion C.1+ cation D.2+ cation

12. Section Check SECTION7.1 Elements with a full octet have which configuration? A.ionic configuration B.halogen configuration C.noble gas configuration D.transition metal configuration

14. Ionic Bonds and Ionic Compounds SECTION7.2 • Describethe formation of ionic bonds and the structure of ionic compounds. • Generalizeabout the strength of ionic bonds based on the physical properties of ionic compounds. • Categorizeionic bond formation as exothermic or endothermic. compound:a chemical combination of two or more different elements

15. Ionic Bonds and Ionic Compounds SECTION7.2 ionic bond ionic compound crystal lattice electrolyte lattice energy Oppositely charged ions attract each other, forming electrically neutral ionic compounds.

16. Ionic Bonds and Ionic Compounds SECTION7.2 Formation of an Ionic Bond • The electrostatic force that holds oppositely charged particles together in an ionic compound is called an ionic bond. • Compounds that contain ionic bonds are called ionic compounds. • Binary ionic compounds contain only two different elements—a metallic cation and a nonmetallic anion.

17. Ionic Bonds and Ionic Compounds SECTION7.2 Formation of an Ionic Bond(cont.)

18. Ionic Bonds and Ionic Compounds SECTION7.2 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.

19. Ionic Bonds and Ionic Compounds SECTION7.2 Properties of Ionic Compounds(cont.) • The strong attractions among the positive and negative ions result in the formation of the crystal lattice. • A crystal latticeis the three-dimensional geometric arrangement of particles, and is responsible for the structure of many minerals.

20. Ionic Bonds and Ionic Compounds SECTION7.2 Properties of Ionic Compounds(cont.) • Melting point, boiling point, and hardness depend on the strength of the attraction.

21. Ionic Bonds and Ionic Compounds SECTION7.2 Properties of Ionic Compounds(cont.) • 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. • An ion in aqueous solution that conducts electricity is an electrolyte.

22. Ionic Bonds and Ionic Compounds SECTION7.2 Properties of Ionic Compounds(cont.) • This figure demonstrates how and why crystals break when an external force is applied.

23. Ionic Bonds and Ionic Compounds SECTION7.2 Energy and the Ionic Bond • Reactions that absorb energy are endothermic. • Reactions that release energy are exothermic.

24. Ionic Bonds and Ionic Compounds SECTION7.2 Energy and the Ionic Bond(cont.) • The energy required to separate 1 mol of ions in an ionic compound is referred to as the lattice energy. • Lattice energy is directly related to the size of the ions that are bonded.

25. Ionic Bonds and Ionic Compounds SECTION7.2 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.

26. Ionic Bonds and Ionic Compounds SECTION7.2 Energy and the Ionic Bond(cont.) • The value of lattice energy is also affected by the charge of the ion.

27. Section Check SECTION7.2 Why are solid ionic compounds poor conductors of electricity? A.They are non-metals. B.They are electrolytes. C.They have electrons that cannot flow freely. D.Solids do not conduct electricity.

28. Section Check SECTION7.2 What is the electrostatic charge holding two ions together? A.covalent bond B.pseudo-noble gas bond C.crystal lattice bond D.ionic bond

30. SECTION7.3 Names and Formulas for Ionic Compounds • Relatea formula unit of an ionic compound to its composition. • Writeformulas for ionic compounds and oxyanions. • Applynaming conventions to ionic compounds and oxyanions. nonmetal:an element that is generally a gas or a dull, brittle solid and is a poor conductor of heat and electricity

31. SECTION7.3 Names and Formulas for Ionic Compounds 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.

32. SECTION7.3 Names and Formulas for Ionic Compounds 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.

33. SECTION7.3 Names and Formulas for Ionic Compounds Formulas for Ionic Compounds(cont.) • A formula unit represents the simplest ratio of the ions involved. • Monatomic ionsare one-atom ions.

34. SECTION7.3 Names and Formulas for Ionic Compounds Formulas for Ionic Compounds(cont.) • Oxidation number, or oxidation state, is the charge of a monatomic ion.

35. SECTION7.3 Names and Formulas for Ionic Compounds Formulas for Ionic Compounds(cont.) • 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.

36. SECTION7.3 Names and Formulas for Ionic Compounds Formulas for Ionic Compounds(cont.) • Polyatomic ionsare ions made up of more than one atom. • 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.

37. SECTION7.3 Names and Formulas for Ionic Compounds Formulas for Ionic Compounds(cont.)

38. SECTION7.3 Names and Formulas for Ionic Compounds Names for Ions and Ionic Compounds • An oxyanionis a polyatomic ion composed of an element (usually a non-metal), bonded to one or more oxygen atoms.

39. SECTION7.3 Names and Formulas for Ionic Compounds Names for Ions and Ionic Compounds(Cont.)

40. SECTION7.3 Names and Formulas for Ionic Compounds Names for Ions and Ionic Compounds(Cont.) • 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.

41. SECTION7.3 Names and Formulas for Ionic Compounds Names for Ions and Ionic Compounds(Cont.)

42. Section Check SECTION7.3 Which subscripts would you most likely use for an ionic compound containing an alkali metal and a halogen? (Remember, 1 = no written subscript) A.1 and 2 B.2 and 1 C.2 and 3 D.1 and 1

43. Section Check SECTION7.3 What is the name of the compound Ca(OH)2? A.calcium oxide B.calcium(I)oxide C.calcium hydroxide D.calcium peroxide

45. Metallic Bonds and the Properties of Metals SECTION7.4 • Describea metallic bond. • Relatethe electron sea model to the physical properties of metals. • Definealloys, and categorize them into two basic types. physical property:a characteristic of matter that can be observed or measured without altering the sample’s composition

46. Metallic Bonds and the Properties of Metals SECTION7.4 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.

47. Metallic Bonds and the Properties of Metals SECTION7.4 Metallic Bonds and the Properties of Metals • 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.

48. Metallic Bonds and the Properties of Metals SECTION7.4 Metallic Bonds and the Properties of Metals(Cont.) • 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 contribute their valence electrons to form a "sea" of electrons. • The electrons are free to move around and are referred to as delocalized electrons, forming a metallic cation.

49. Metallic Bonds and the Properties of Metals SECTION7.4 Metallic Bonds and the Properties of Metals(Cont.) • A metallic bondis the attraction of an metallic cation for delocalized electrons.

50. Metallic Bonds and the Properties of Metals SECTION7.4 Metallic Bonds and the Properties of Metals(Cont.) • Boiling points are much higher than melting points because of the energy required to separate atoms from the groups of cations and electrons.