1. Chapter 5 Ionic Compounds  What holds compounds together? Chemical bonds- forces of attraction between atoms Why are the Noble Gases stable? The outer level is full  low reactivity How many electrons are in the outer level? 8 except for Helium(2)

2. Octet Rule  Main-block elements form bonds so that an atom has 8 e - in the outer energy level  The energy needed to break the bonds is called Bond Energy  Measured in kJ/mole

3. What is it called if an atom gives up an electron?  Cation- ion with a positive charge  Metals tend to be cations  What if an atom gains an electron?  Anion- ion with a negative charge  Nonmetals tend to be anions

4. What type of bond forms from opposite charged ions?  Ionic Bond- bond between oppositely charged ions  How do we know what charge an atom will have?  Main-block elements have one charge  Group IA  1 valence electron  1 +

5. Con.  Group IIA  2 +  Group IIIA  3 +  Group IVA  4 + or 4 -  Group VA  3 -  Group VIA  2 -  Group VIIA  1 -

6. What are these compounds called?  Ionic Compounds- compounds that form from ionic bonding -they have a net charge of zero The best example of ionic compounds are Salts -excluding H + cations and OH - and O 2- anions -Properties of salts 1.High melting points 2.High boiling points 3.Hard 4.Brittle

7. How do you name Ionic Compounds? A.Binary Ionic(Type I) Compounds- involves only 1 charge(cation and anion) 1. Name the monatomic cation- use the full metal name 2. Name the monatomic anion- use the root of the anion and add “ide” Example: Ca 2+, Cl Calcium chloride What would the formula be? CaCl 2

8. Con. B.Binary Ionic (Type II) compound- involves elements with more than one charge; transition elements can have more than one charge Follow the same steps as Type I but use Roman numerals to indicate charge Example: Fe 2+, Cl - Fe 3+, Cl - Iron(II) chloride Iron (III) chloride FeCl 2 FeCl 3

9. Con. C.Ionic compounds with Polyatomic Ions What are Polyatomic Ions? -ion made of 2 or more atoms bonded together that act as a single ion  has one charge How do we name them? 1.Name the monoatomic or polyatomic cation 2.Name the monoatomic or polyatomic anion Example: NH 4 +, Cl - Ammonium chloride (NH 4 )Cl

10. Empirical Formulas  Simplest whole number ratio of atoms in a compound

11. Molar mass of compounds 1.List the moles of each element 2.Set up a mole ratio 3.Add the total

12. Percent Composition  Determining the % of each element in a compound mass of element 100 total mass This gives us the % by mass of the element

13. Example  Determine the percent composition of each element of copper(I) sulfide.  Determine the percent composition of each element in Mg(OH) 2 and (NH 4 )(NO 3 )

14. Steps to determine the Empirical Formula 1.% to mass 2.Mass to moles 3.Divide by small 4.Multiply til whole Example: One compound is composed of 63% manganese and 37% oxygen. What is the empirical formula?

15. Another example  Determine the empirical formula of a compound if it contains 76.7% cadmium, 21.9% oxygen, and 1.4% hydrogen.