Chapters 8 & 9

1. Chapters 8 & 9 Naming Compounds Writing Formulas

2. Compounds • Follow the Law of Definite Proportion. • Have a constant composition. • Have to add the same number of atoms every time. • Two types.

3. Two Types of Compounds 1 Ionic Compounds • Made of cations and anions. • Metals and nonmetals. • The electrons lost by the cation are gained by the anion. • The cation and anions surround each other. • Smallest piece is a FORMULA UNIT.

4. Crystalline Structure – Ionic Compound

5. Two Types of Compounds 2 Molecular Compounds • Made of molecules. • Made by joining nonmetal atoms together into molecules. • H2O, CO2, C6H12O6

6. Chemical Formulas • Shows the kind and number of atoms in the smallest piece of a substance. • Molecular formula- number and kinds of atoms in a molecule. • CO2 • C6H12O6

7. Two Types of Compounds Ionic Molecular Smallest Piece Formula Unit Molecule Types of Elements Metal and Nonmetal Nonmetals Solid, Liquid or Gas State Solid Melting Point High >300ºC Low <300ºC

8. Chemical Formulas • More than one atom? –use a subscript (H2O) • There are 7 diatomic elements • Hydrogen (H2), Nitrogen (N2), Oxygen (O2), Fluorine (F2), Chlorine (Cl2), Bromine (Br2), and Iodine (I2) • Remember: “Br I N Cl H O F”

9. +1 +2 +3 -3 -2 -1

10. Systematic Naming • There are too many compounds to remember the names of them all. • Compound is made of two or more elements. • Put together atoms. • Name should tell us how many and what type of atoms.

11. Naming Ions • We will use the systematic way. • Cation- if the charge (oxidation #) is always the same, use name of the metal. • Transition metals can have more than one charge or oxidation number. • Therefore, indicate the charge with roman numerals in parenthesis. • Fe+3 is named - iron (III) ion Movie

12. Exceptions: • Some of the transition metals have only one ionic charge: • Do not use roman numerals for these: • Silver is always 1+ (Ag1+) • Cadmium and Zinc are always 2+ (Cd2+ and Zn2+)

13. Metals with Multiple Charges Transition Metals Here it is easier to list the ones that only have a single common oxidation state. All Group 3B - 3+ Ni, Zn, Cd - 2+ Ag - 1+ Lanthanides and actinides - 3+

14. Name These Ions • Na+1 • Ca+2 • Al+3 • Fe+3 • Fe+2 • Pb+2 • Li+1 sodium ion calcium ion aluminum ion iron (III) ion iron (II) ion lead (II) ion lithium ion

15. Write Formulas for These • Potassium ion • Magnesium ion • Copper (II) ion • Chromium (VI) ion • Barium ion • Mercury (II) ion K+1 Mg+2 Cu+2 Cr+6 Ba+2 Hg+2

16. Naming Anions • Anions are always the same. • Change the element ending to – ide • F-1 Fluorine

17. Naming Anions • Anions are always the same. • Change the element ending to – ide • F-1 Fluorin

18. Naming Anions • Anions are always the same • Change the element ending to – ide • F-1 Fluori

19. Naming Anions • Anions are always the same • Change the element ending to – ide • F-1 Fluor

20. Naming Anions • Anions are always the same • Change the element ending to – ide • F-1 Fluori

21. Naming Anions • Anions are always the same • Change the element ending to – ide • F-1 Fluorid

22. Naming Anions • Anions are always the same • Change the element ending to – ide • F-1 Fluoride

23. Name These Ions • Cl-1 • N-3 • Br-1 • O-2 • Ga+3 Chloride Nitride Bromide Oxide Gallium (III)

24. Write These • sulfide ion • iodide ion • phosphide ion • strontium ion S-2 I-1 P-3 Sr+2

25. Polyatomic Ions • Groups of atoms that stay together and have a charge. • Use your reference sheet • Acetate C2H3O2-1 • Nitrate NO3-1 • Nitrite NO2-1 • Hydroxide OH-1 • Permanganate MnO4-1 • Cyanide CN-1

26. Polyatomic Groups with a Charge

27. Sulfate SO4-2 Sulfite SO3-2 Carbonate CO3-2 Chromate CrO4-2 Dichromate Cr2O7-2 Phosphate PO4-3 Phosphite PO3-3 Ammonium NH4+1 Polyatomic Ions

28. Common Polyatomic Ions

29. Ionic Compounds We’ve named the ions, so now it is time to name the compounds!

30. Naming Binary Ionic Compounds • Binary Compounds - 2 elements. • Ionic - a cation and an anion. • To write the names just name the two ions. • Easy with Representative elements. • NaCl = Na+ Cl- = sodium chloride • MgBr2 = Mg+2 Br- = magnesium bromide

31. Naming Binary Ionic Compounds • The problem comes with the transition metals. • Need to figure out their charges. • The compound must be neutral. • Same number of + and – charges. • Use the anion to determine the charge on the positive ion.

32. Balancing Charges How many zinc +2 charges are needed to balance phosphide’s -3 charge? What subscripts must be placed on the line? The numbers used must always be whole numbers.

34. Naming Ionic Compounds Many metals form more than one compound with some anions. For these, roman numerals are used in the name to indicate the charge on the metal. Cu1++O2- = Cu2O copper(I) oxide copper(I) oxide Cu2++O2- = CuO copper(II) oxide copper(II) oxide

35. More Examples FeCl2 iron(II) chloride FeCl3 iron(III) chloride SnS tin(II) sulfide SnS2 tin(IV) sulfide AgCl silver chloride CdS cadmium sulfide • Note • Some transition metals only have a single state • so the roman numeral may be omitted. • Some main group metals, with high atomic number • have more than one state, roman numbers are used.

36. Naming Binary Ionic Compounds • Write the name of CuO • Need the charge of Cu • O is -2 • Copper must be +2 • Copper (II) oxide • Name CoCl3 • Cl is -1 and there are three of them = -3 • Co must be +3 Cobalt (III) chloride

37. Naming Binary Ionic Compounds • Write the name of Cu2S. • Since S is -2, the Cu2 must be +2, so each one is +1. • copper (I) sulfide • Fe2O3 • Each O is -2 3 x -2 = -6 • 2 Fe must = +6, so each is +3. • iron (III) oxide

38. Naming Binary Ionic Compounds • Write the names of the following • KCl • Na3N • CrN • Sc3P2 • PbO • PbO2 • Na2Se Potassium Chloride Sodium Nitride Chromium (III) Nitride Scandium (II) Phosphide Lead (II) Oxide Lead (IV) Oxide Sodium Selenide

39. Ternary Ionic Compounds • Will have polyatomic ions • At least three elements • Name the ions • NaNO3 • CaSO4 • CuSO3 • (NH4)2O Sodium Nitrate Calcium Sulfate Copper (II) Sulfite Ammonium Oxide

40. Ternary Ionic Compounds • LiCN • Fe(OH)3 • (NH4)2CO3 • NiPO4 Lithium Cyanide Iron (III) Hydroxide Ammonium Carbonate Nickel (III) Phosphate

41. Writing Formulas • The charges have to add up to zero. • Get charges on pieces. • Cations from name of table. • Anions from table or polyatomic. • Balance the charges by adding subscripts. • Put polyatomics in parenthesis.

42. Writing Formulas • Write the formula for calcium chloride. • Calcium is Ca+2 • Chloride is Cl-1 • Ca+2 Cl-1 would have a +1 charge. • Need another Cl-1 • Ca+2 Cl2-1

43. Write the Formulas for These Li2S SnO SnO2 MgF2 CuSO4 FeP GaNO3 Fe2S3 • lithium sulfide • tin (II) oxide • tin (IV) oxide • magnesium fluoride • copper (II) sulfate • iron (III) phosphide • gallium (I) nitrate • iron (III) sulfide

44. Write the Formulas for These • ammonium chloride • ammonium sulfide • barium nitrate NH4Cl (NH4)2S Ba(NO3)2

45. Things To Look For • If cations have (roman #), the number is their charge. • If anions end in -ide they are probably off the periodic table (Monoatomic) • If anion ends in -ate or -ite it is polyatomic

46. Molecular Compounds Writing Names and Formulas

47. Molecular Compounds • made of just nonmetals • smallest piece is a molecule • can’t be held together because of opposite charges • can’t use charges to figure out how many of each atom

48. Easier • Ionic compounds use charges to determine how many of each. • Have to figure out charges. • Have to figure out numbers. • Molecular compounds name tells you the number of atoms. • Uses prefixes to tell you the number

49. Prefixes • 1 mono- • 2 di- • 3 tri- • 4 tetra- • 5 penta- • 6 hexa- • 7 hepta- • 8 octa-

50. Prefixes • 9 nona- • 10 deca- • To write the name write two words