1. Warm Up Give the formula that will result from reacting the following ions: 1.Na +, O 2- 2.Al 3+, Cl - 3.Mg 2+, N 3- 4.Al 3+, S 2- 5.Ca +, Br - 1.Na 2 O sodium oxide 2.AlCl 3 aluminum chloride 3.Mg 3 N 2 magnesium nitride 4.Al 2 S 3 aluminum sulfide 5.No such thing as Ca +, can only be 2+ cation

2. Ionic Bonds and Compounds Section 7.2

3. Understand how ionic bonds are formed Know that ionic compounds come from cation and anion attraction to each other Get a feel for the structure and properties of ionic solids Learning Objectives

4. Chemical bond: attractive force holding two or more atoms together. Covalent bond results from sharing electrons between the atoms. Usually found between nonmetals. Ionic bond results from the transfer of electrons from a metal to a nonmetal. Metallic bond: attractive force holding pure metals together. Overview of Bonding

5. Ionic Bonds An ionic bond is typically formed between a metal and a non-metal. Metals have low electronegativities (less than 2.0), while non-metals have high electronegativities (above 2.0). Consequently, the non-metal is "stronger" than the metal, and can steal electrons very easily from the metal. This results in the metal becoming a cation, and the non-metal becoming an anion.

6. Ionic Bonds

8. Ionic bonds are not about sharing electrons rather …. The more electronegative element (anion to be) simply steals the electron(s) from the more electropositive element (cation to be).

9. Ionic Bonds

10. Ionic Bonds-Simple Animation Sodium Fluoride

11. Ionic Compound Structure

13. Ionic Compounds  Cations and anions are attracted by electrostatic forces to form ionic bonds  Bonding occurs to create an electrically neutral ionic compound  Chemical formula for ionic compounds called formula unit

14. Properties of Ionic Crystals  Most ionic compounds are crystals at room temperature  Attraction of + and - ions results in a stable structure = high melting temperature

15. Ionic vs. Covalent Ionic Covalent CompoundsCompounds –Gases, liquids, or solids –Low melting and boiling points-moth balls –Poor electrical conductors –Many soluble in nonpolar liquids but not in water –Crystalline solids –High melting and boiling points –Conduct electricity when melted –Many soluble in water but not in nonpolar liquid

16. Coordination Number  Coordination number is the number of ions of opposite charge that surround the ion in a crystal

17. Pretty Ionic Solids CaF 2 (fluorite) HgS (cinnabar) FeS 2 (pyrite) PbMoO 4 (wulfenite) CaCO 3 (aragonite) TiO 2 (rutile)