Ionic Compounds and Metals

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

2. BIG IDEA Atoms in ionic compounds are held together by chemical bonds formed by the attraction of oppositely charged ions.

3. 7.1Ion Formation

4. Ions are formed when atoms gain or lose valence electrons to achieve a stable octet electron configuration. 7.1 Main Idea

5. Define a chemical bond. • Describe the formation of positive and negative ions • Relate ion formation to electron configuration. 7.1

6. Review Vocabulary & Concepts • Ion • Valence electron • Octet • Electron configuration • Lewis-dot diagrams • Electron affinity

7. New Vocabulary • Chemical bond • Ionic bond • Cation • Anion

8. Chemical Bond • The force that holds two atoms together • Ionic bonds *Chap 7 • Metallic bonds *Chap 7 • Covalent bonds *Chap 8

9. Valence Electrons and Chemical Bonds • Each valence electron is represented as a dot around the nuclear core of the element.

10. Valence Electrons and Chemical Bonds • The most stable electron configuration for an element is the nearest noble gas. • ns2np6 • Octet • Ions gain or lose electrons to achieve noble gas configurations

11. Formation of Ions

12. Positive Ion Formation • Cation: a positively charged ion • Results when electrons are lost

13. Metal ions • Group 1 loses 1 electron +1 charge • Group 2 loses 2 electrons +2 charge • Group 13 loses 3 electrons +3 charge • Groups 3-12 usually lose 2 electrons Most have +2 charge (range from +1 to +3)

14. Negative Ion Formation • Anion: negatively charged ion • Formed when electrons are gained • Non-metals

15. Nonmetal Ions • Group 15 gains 3 electrons 3- charge • Group 16 gains 2 electrons 2- charge • Group 17 gains 1 electron 1- charge

16. Section Summary • A chemical bond is the force that holds two atoms together • Some atoms gain or lose electrons to gain a stable configuration; these are called ions • Most stable configurations end: ns2np6.

17. Can you… • Define a chemical bond. • Describe the formation of positive and negative ions • Relate ion formation to electron configuration.

18. 7.2Ionic Bonds and Ionic Compounds

19. Oppositely charged ions attract each other forming electrically neutral ionic compounds. 7.2 Main Idea

20. Describe the formation of ionic bonds and the structure of ionic compounds • Generalize about the strength of ionic bonds based on the physical properties of ionic bonds • Categorize ionic bond formation as exothermic or endothermic 7.2

21. Review Vocabulary & Concepts • Compound • Chemical bond • Physical property • Chemical property • Electronegativity

22. New Vocabulary • Ionic bond • Ionic compound • Crystal lattice • Binary compound • Electrolyte

23. Formation of an Ionic Bond • Electrons are exchanged between atoms • Increases stability of both • Ions are held together by the opposite charges

24. Definition of Ionic Bond • Atoms with a difference in electronegativity of 1.7 or greater • Crystallize as sharply defined particles

27. VideoAnother Video

28. Binary Ionic Compounds • Formed from a metal and a non-metal • Contain only two elements • Examoples • NaCl • MgO • CaCl2 • Fe2O3

29. Formation of Ionic Compounds • Net charge on all ions in a compound must be zero (0)! • More on this later!!!

30. Properties of Ionic Compounds • Crystal Lattice: Highly organized crystal of cations and anions Anion Cation

32. Properties of Ionic Compounds • Crystalline shape depends on the ions involved

33. Properties of Ionic Compounds • Physical properties • Very strong • Solid at normal temperatures • Very high melting point and boiling point • Many have brilliant colors due to transition metals • Hard, rigid • Brittle

34. Properties of Ionic Compounds • Conductivity (ability for electric charge to move through a substance • Solids have electrons locked in place • Non conductive • Aqueous solutions have easily moveable electrons • Electrolytes • Good conductors

35. Water and ionic bonds

36. Properties of Ionic Compounds • Formation of lattice is always exothermic.

37. Section Summary • Ionic compounds contain ionic bonds formed by the attraction of oppositely charged ions. • Ions in an ionic compound are arranged in a repeating pattern called a lattice. • Ionic compounds are electrolytes; they conduct electricity in liquid and aqueous states.

38. Can you… • Describe the formation of ionic bonds and the structure of ionic compounds • Generalize about the strength of ionic bonds based on the physical properties of ionic bonds • Categorize ionic bond formation as exothermic or endothermic

39. 7.3 Names and Formulas for Ionic Compounds

40. In written names and formulas for ionic compounds, the cation appears first, followed by the anion. 7.3 Big Idea

41. Relate a formula unit of an ionic compound to its composition Write formulas for ionic compounds and oxyanions. Apply naming conventions to ionic compounds and oxyanions. 7.3 Objectives

42. Review Vocabulary & Concepts • Anion • Cation • Metal • Non-metal

43. New Vocabulary • Formula unit • Monatomic ion • Polyatomic ion • Oxidation number • Oxyanion

44. Describing Ionic Compounds • Formula unit- simplest way to indicate the composition of an ionic substance • NaCl • MgCl2

45. Monatomic Ions • Ions in which only one element is present • Na+, Cl-, Mg2+, P3-

46. Oxidation number • Fancy word for “charge” • aka oxidation state • Transition metals may have multiple oxidation states • Must tell the oxidation state • Ex: Iron 2+ is Iron II; Iron 3+ is Iron III

47. Formulas for Binary Ionic Compounds • CxAy • C is cation • A is anion • x number of cations in one unit • y is number of anions in one unit

48. Rules for writing formula units • CxAy • Cation is always first • Anion is always second • Net oxidation MUST BE ZERO

49. Tried and True Method • Write out each ion. • Place oxidation number under each ion • Cross multiply • Reduce to simplest form

50. Write out each ion. • Sodium and chlorine Na Cl