1. + Ionic Bonds and Ionic Compounds Forming Compounds from Ions

2. + Objectives When you complete this presentation, you will be able to … explain the electrical charge of an ionic compound. describe three properties of ionic compounds.

3. + Formation of Ionic Compounds: Introduction Ionic compounds are composed of a mixture of cations (ions with positive charges) anions (ions with negative charges) Cations are usually metal ions. Anions are usually nonmetal ions. The compounds are usually electrically neutral.

4. + Formation of Ionic Compounds: Ionic Bonds Cations and anions have opposite charges. They are attracted to each other by electrostatic forces. These forces are called ionic bonds.

5. + Bonds are formed by an exchange of electrons. For example: Na+Cl ➞ Na + +Cl – Formation of Ionic Compounds: Ionic Bonds The NaCl formed is a neutral compound.

6. + Bonds are formed by an exchange of electrons. For example: Formation of Ionic Compounds: Ionic Bonds Ca+Cl ➞ Ca 2+ +Cl – +Cl+Cl – The CaCl 2 formed is a neutral compound.

7. + Ionic compounds are composed of equal numbers of positive charges and negative charges. NaCl CaCl 2 Formation of Ionic Compounds: Formula Units

8. + A chemical formula is meant to represent the kinds and numbers of atoms in the simplest representative unit of the compound. For example: C 6 H 12 O 6 indicates that there are six carbon atoms, twelve hydrogen atoms, and six oxygen atoms in the compound glucose. For example: NaCl indicates that there is one sodium atom (ion) for each chloride atom (ion) in the compound of sodium chloride. Formation of Ionic Compounds: Formula Units

9. + Ionic compounds (like sodium chloride) exist as large collections of ions (+ and –) and not as a collection of discrete molecules (like glucose). This means that we use the lowest whole number ratio for the chemical formulas of ionic compounds. These are called formula units. Formation of Ionic Compounds: Formula Units

10. + Most ionic compounds are crystalline solids at room temperature. For example: sodium chloride (NaCl) For example: aragonite (CaCO 3 ) For example: rutile (TiO 2 ) Ionic compounds generally have high melting points. Properties of Ionic Compounds

11. + Each ion in an ionic compound has a certain number of oppositely charged ions surrounding it. That number is called the coordination number. Properties of Ionic Compounds

12. + For example: In sodium chloride (NaCl), each Na + is surrounded by six Cl – and each Cl – is surrounded by six Na +. The coordination number of Na + is six. The coordination number of Cl – is six. Properties of Ionic Compounds

13. + For example: In cesium bromide (CsBr), each Cs + is surrounded by eight Br – and each Br – is surrounded by eight Cs +. The coordination number of Cs + is eight. The coordination number of Br – is eight. Properties of Ionic Compounds

14. + For example: In titanium dioxide (TiO 2 ), each Ti 4+ is surrounded by six O 2– and each O 2– is surrounded by three Ti 4+. The coordination number of Ti 4+ is six. The coordination number of O 2– is three. Properties of Ionic Compounds

15. + Ionic compounds are generally conductive when melted or dissolved in water. When an ionic compound is melted the orderly arrangement of ions is destroyed the ions are free to migrate as they please an electric voltage will cause the cations to migrate to one pole and the anions to migrate to the other pole. Properties of Ionic Compounds

16. + Something similar happens when an ionic compound dissolves in water. Properties of Ionic Compounds

17. + Ionic compounds are composed of a mixture of cations (ions with positive charges) and anions (ions with negative charges) Cations are usually metal ions and anions are usually nonmetal ions. Ionic compounds are usually electrically neutral. Summary

18. + Cations and anions are attracted to each other by electrostatic forces called ionic bonds. Bonds are formed by an exchange of electrons. Ionic compounds are composed of equal numbers of positive charges and negative charges. Summary

19. + Cations and anions are attracted to each other by electrostatic forces called ionic bonds. The chemical formulas for ionic compounds use the lowest whole number ratio for the chemical formulas of ionic compounds which are called formula units. Summary

20. + Cations and anions are attracted to each other by electrostatic forces called ionic bonds. Most ionic compounds are crystalline solids at room temperature. Ionic compounds generally have high melting points. Summary

21. + Each ion in an ionic compound has a certain number of oppositely charged ions surrounding it which is called the coordination number. Ionic compounds are generally conductive when melted or dissolved in water. Summary